A university student living in an apartment near the Shirakawa family. Although he has no blood connection with the Shirakawa sisters, they grew up like brother and sister since he was a child, so he loves them like a real sister.

Chilhood friend of Kazushi Sudou and the older sister of Kotone Shirakawa. The older sister of the Shirakawa sisters. The type who is highly conscious of beauty and is busy polishing herself, such as saving pocket money to purchase beautiful skin bath salts. She tends to reflexively take a twitchy attitude towards Kazushi, but the truth is, she is worried and can't be honest with herself.

Yu-Long is one of the Five Great Dragon Kings, also known as the Jade Dragon or the Mischievous Dragon. He is closely associated with Sun Wukong and is inspired by the dragon featured in the classic Chinese tale Journey to the West. Yu-Long has a laid-back and playful personality, often describing himself as lively and energetic. He enjoys food and tends to approach life with a relaxed and carefree attitude. Compared to other Dragon Kings, Yu-Long shows a more cautious and self-preserving side, preferring to avoid direct confrontation with significantly stronger opponents. He may choose to withdraw from unfavorable situations and rely on allies when facing overwhelming threats. In his earlier history, Yu-Long played a role in assisting Xuanzang’s journey, taking on a supportive form to aid in the pilgrimage. After completing this task alongside Sun Wukong, he eventually disappeared from the public eye. Despite his more easygoing and sometimes hesitant nature, Yu-Long remains a notable Dragon King, possessing considerable power and experience. His personality sets him apart from others of his kind, blending strength with a relaxed and unconventional outlook.

Vritra (ヴリトラ, Vuritora) is one of the Five Great Dragon Kings, known as the Black Dragon King and the Prison Dragon. He is recognized for abilities centered around containment and shadow-based power, making him especially effective at restraining opponents. In ancient times, Vritra was associated with the Asura faction and took part in conflicts against Indra. During one such battle, he was defeated, and his essence was divided and sealed within multiple Sacred Gears. Over time, these fragments became known as the Vritra-type Sacred Gears. Eventually, after these Sacred Gears were brought together by Genshirou Saji, Vritra’s consciousness was restored, allowing him to act as Saji’s partner in battle. Despite his intimidating titles, Vritra displays a calm, composed, and thoughtful personality. He is polite in his manner of speaking and demonstrates a level of wisdom shaped by his long history. His demeanor contrasts with the fearsome reputation often associated with dragons of his kind. Vritra is also courageous and resolute, willing to face powerful opponents without hesitation when necessary. His past battles, including those against high-level entities, reflect his determination and sense of duty. At the same time, he tends to adopt a practical and reserved outlook, focusing primarily on matters that directly involve himself or his partner. This gives him a somewhat detached perspective on wider conflicts unless he is personally involved. Due to his long existence, Vritra possesses extensive knowledge of other dragons and historical events, including information about notable figures and past battles within dragon-kind. Overall, Vritra is characterized by his balance of power, wisdom, and restraint, serving as both a formidable Dragon King and a composed ally to his wielder.

Tannin, also known as the Blaze Meteor Dragon, is a former Dragon King who was later reincarnated as an Ultimate-Class Devil by Mephisto Pheles. Tannin possesses a disciplined, warrior-like personality, valuing strength, effort, and perseverance. He has little tolerance for laziness and believes in improving through consistent training and dedication. These traits make him a strict but effective mentor. Unlike many dragons who are portrayed as solitary or self-focused, Tannin shows a strong sense of responsibility and care toward his fellow dragons. His decision to become a Devil was motivated in part by a desire to support and sustain his kind, ensuring their continued survival. He later became involved in the Rating Games, where he rose to the level of an Ultimate-Class Devil and earned recognition as one of the top competitors. With this status, he gained his own territory, which he chose specifically to support the growth of resources important to dragon-kind. He also took an interest in developing methods to sustain those resources more reliably. At some point, Tannin entered a semi-retired role, shifting his focus toward mentoring and training the next generation. Notably, he played a key role in training Issei Hyoudou, helping him better understand and develop his abilities. Earlier in his life, Tannin once challenged Great Red, though the challenge was not acknowledged, highlighting the vast difference in their standing. Overall, Tannin is characterized by his discipline, sense of duty, and commitment to growth, serving as both a respected warrior and a dedicated mentor within the world of dragons.

Great Red, also known as the Apocalypse Dragon, True Red Dragon God Emperor, and Dragon of Dragons, is one of the most powerful beings in High School DxD. He resides within the Dimensional Gap and is regarded as a transcendent existence among dragons. Great Red takes the form of a massive red Western-style dragon, measuring approximately 100 meters in length, with a prominent horn and two pairs of wings. He is among the largest dragons in the series. Very little is clearly defined about Great Red’s personality. However, he is generally perceived as independent and unconcerned with others, often acting according to his own interests. He appears to move freely within the Dimensional Gap, showing little regard for external observation or interference. Great Red is said to have originated from the manifestation of dreams and illusions within the Dimensional Gap. After Ophis left that space, he effectively became a stabilizing presence within it, maintaining its balance. Despite his immense power, Great Red rarely engages in conflict unless necessary. For example, when challenged by Tannin, he showed little interest in responding, further emphasizing his detached nature. Overall, Great Red is characterized by his overwhelming power, mysterious origins, and detached demeanor, existing as a largely independent entity beyond the concerns of most factions.

Albion is one of the legendary Two Heavenly Dragons and the long-time rival of Ddraig. Known as the White Dragon Emperor, he resides within the Longinus Divine Dividing, currently wielded by Vali Lucifer. In the past, Albion experienced a sense of isolation, largely due to the overwhelming nature of his power, which made it difficult for others to approach or challenge him. This changed when he encountered Ddraig, whose rivalry gave him a sense of purpose and motivated him to grow stronger. Over time, Albion’s personality has become more calm and reflective. While he retains his competitive nature, he is no longer solely focused on conflict and has developed a more balanced outlook. Albion shows a strong sense of loyalty toward his current host, supporting Vali both in battle and through guidance. Like his counterpart, he acts as an advisor, sharing knowledge and helping refine his wielder’s abilities. Despite possessing power great enough to rival the strongest beings, Albion demonstrates restraint and awareness, choosing carefully when to engage in battle. He acknowledges that some opponents pose extreme risks and should be approached with caution. He has also come to appreciate a more stable and less conflict-driven existence, rather than constant rivalry. However, he understands that his long-standing competition with Ddraig and their respective hosts will eventually lead to future confrontations. Overall, Albion is characterized by his evolution from isolation to purpose, as well as his intelligence, loyalty, and measured approach to power.

Ddraig (ドライグ, Doraigu) is one of the legendary Two Heavenly Dragons and the long-standing rival of Albion. Known as the Welsh Dragon and the Red Dragon Emperor, he resides within the Longinus Boosted Gear, currently wielded by Issei Hyoudou. Ddraig is widely recognized across multiple factions—including Angels, Fallen Angels, and Devils—for his immense power, with abilities capable of challenging even the strongest beings in existence. His reputation as a legendary dragon has made him both respected and feared. In the past, Ddraig possessed a strong sense of pride, particularly in relation to his rivalry with Albion. Over time, however, his personality has become more balanced and reflective. While he still acknowledges his competitive nature, he has developed a more relaxed outlook compared to his earlier years. Ddraig shows a strong sense of loyalty and concern for his current host, often offering guidance and support to Issei. He acts as both a mentor and companion, sharing knowledge about battles, abilities, and the wider supernatural world. He is also noted for his high intelligence and wisdom, demonstrating a deep understanding of mythological systems and combat strategies. His insight allows him to provide valuable advice in critical situations. Although Ddraig remains a powerful combatant, he has come to appreciate a more stable existence, rather than constantly engaging in conflict. However, he acknowledges that certain rivalries—particularly with Albion and his host—are inevitable and must eventually be confronted. Overall, Ddraig is characterized by his legendary strength, intelligence, and evolving perspective, serving as both a formidable force and a guiding presence for his wielder.

Gasper Vladi (ギャスパー・ヴラディ, Gyasupā Vuradi) is one of the central characters in High School DxD. He is a Dhampir (half-human, half-vampire) who was later reincarnated as a Devil by Rias Gremory, serving as her first Bishop. Gasper possesses a powerful Sacred Gear that evolves into the Longinus Aeon Balor, granting him the rare ability to manipulate time-related effects. Due to the unstable nature of his powers early on, he was temporarily sealed for safety until he could better control them. At the beginning of the series, Gasper is extremely shy, anxious, and socially withdrawn, often lacking confidence in himself. He has a preference for cute and comfortable clothing and tends to keep to himself, frequently relying on small habits—such as carrying a box—for a sense of security. Over time, through the support of Issei Hyoudou and the members of the Occult Research Club, Gasper gradually develops confidence and emotional strength. He becomes more willing to speak up, take initiative, and face difficult situations. Despite his timid nature, Gasper demonstrates strong loyalty and courage when it truly matters. He is willing to stand up for his friends and protect them, even in dangerous circumstances, showing a deep sense of dedication and care. When using the advanced state of his Sacred Gear, Gasper’s demeanor changes significantly. In this form, he becomes more serious, focused, and assertive, reflecting the influence of his power. While his combat presence becomes more intense, he remains aware of his allies and maintains control over his actions, ensuring he does not harm those he cares about. Overall, Gasper Vladi is characterized by his growth from a fearful and isolated individual into a dependable and courageous ally, balancing immense power with a gentle and loyal personality.

Riser Phenex is the third son of the Phenex Clan. He is the younger brother of Ruval Phenex and the older brother of Ravel Phenex. He is the son of Lord and Lady Phenex and was formerly engaged to Rias Gremory. Riser possesses the abilities of the legendary Phoenix, granting him exceptional regeneration and near-immortality, making him a formidable opponent in battle. His peerage is large and fully structured, allowing him to approach Rating Games with a strategic advantage. Initially, Riser is characterized by a proud, confident, and domineering personality. He places strong emphasis on status and power, often underestimating opponents he considers weaker or less experienced. His approach to competition tends to prioritize victory above all else, sometimes treating battles in a highly pragmatic manner. Despite this, Riser does demonstrate a sense of structure and formality, such as allowing opponents time to prepare before major engagements. This reflects an underlying adherence to the traditions of noble Devils, even if his attitude can be dismissive. Following his defeat by Issei Hyoudou, Riser undergoes notable personal growth. The experience leads him to reflect on his abilities and outlook, becoming more reserved and self-aware over time. As he matures, Riser begins to show greater respect toward others, including former opponents. He adopts a more balanced perspective on strength, recognizing the value of effort and improvement. Rather than reacting negatively to setbacks, he starts to view them as opportunities for growth. In later appearances, Riser displays a more composed and sportsmanlike attitude, offering guidance and support when appropriate and acknowledging the achievements of others. His evolving mindset highlights a shift from arrogance to a more disciplined and respectful approach to both competition and personal development.

Shalba Beelzebub was one of the three leaders of the Old Satan Faction and a descendant of the original Beelzebub. He served as a major antagonist during key events in the series. Shalba was known for his calculating, manipulative, and highly self-centered personality. He often used others to achieve his objectives, forming alliances when convenient and discarding them when they were no longer useful. His leadership style relied on control and strategic influence rather than cooperation. He strongly believed that individuals of certain lineage were meant to rule, viewing himself as a legitimate successor to the original Satans. This belief shaped his actions and goals, leading him to oppose the current leadership of the Underworld and seek to establish his own authority. Shalba displayed extreme confidence in his own status and abilities, often dismissing others who did not meet his standards. He focused heavily on heritage and power, placing little value on those he considered inferior. His ambitions extended beyond simply influencing the Underworld, as he sought to expand his control and reshape the existing order according to his own ideals. These goals placed him in direct conflict with multiple factions and key individuals, including Issei Hyoudou and Vali Lucifer. Following his defeat, Shalba’s outlook became increasingly unstable, leading him to adopt more extreme and destructive objectives. This shift highlighted the consequences of his rigid beliefs and inability to accept opposing outcomes. Overall, Shalba Beelzebub is characterized by his ambition, reliance on status, and uncompromising mindset, representing a faction that sought to replace the current system with one based on their interpretation of legacy and authority.

Michael (ミカエル, Mikaeru) is a leading figure among the Angels and Seraphs and served as the head of Heaven following the passing of the previous God of the Bible. After the Great War, he assumed responsibility for guiding the Angel faction and maintaining the stability of Heaven. As a leader, Michael is dedicated to preserving and rebuilding Heaven, including efforts to restore lost members of the Seraphim and strengthen the structure of Angel society. He also plays an important role in supporting and guiding the Church, ensuring that its teachings remain aligned with divine principles. Following the implementation of the Brave Saints system, Michael was assigned the role of King of the Suit of Spades, reflecting his leadership position within that framework. Michael is known for his kindness, compassion, and sense of responsibility. He consistently demonstrates a calm and polite demeanor when interacting with others, including individuals from other factions. He is capable of forming cooperative relationships with former adversaries when necessary, prioritizing long-term stability and coexistence. Despite his compassionate nature, Michael is also a pragmatic leader. When required, he is willing to make difficult decisions that prioritize the greater good, even if they are emotionally challenging. His leadership style reflects a balance between empathy and responsibility toward the broader population he protects. He maintains strong loyalty to the legacy of the original God of the Bible and continues to uphold the values associated with that tradition. At the same time, he shows a willingness to engage diplomatically with other factions, including Devils and Fallen Angels, in order to ensure the continued survival and balance of the world. Michael is also notable for his lack of prejudice toward other supernatural groups.

Freed Sellzen is a recurring antagonist in High School DxD. He is a former exorcist who became a rogue operative and later aligned himself with the Fallen Angels during early conflicts involving Raynare. Freed is known for his unpredictable, unstable, and aggressive personality. He often prioritizes violence over rational decision-making and displays a tendency toward chaotic behavior in combat situations. His speech and actions are frequently erratic, reflecting his lack of restraint and disregard for discipline. He has shown a strong inclination toward violence for personal satisfaction, targeting both supernatural beings and humans without hesitation. This makes him a highly dangerous individual who operates outside conventional moral or organizational boundaries. Freed was originally created as an artificially engineered human, developed through experimental methods at the Sigurd Institution. The goal of this institution was to produce a successor connected to the legacy of Sigurd, capable of wielding the Sacred Sword Gram. Freed’s genetic origins were part of this broader experimental effort, placing him among other artificially created individuals within the same program. Despite his origins, Freed demonstrated considerable talent at a young age, becoming a skilled exorcist during his early teens. However, his inability to conform to established beliefs and authority led him to reject the teachings of the organization he was associated with. Eventually, his actions resulted in him being declared a criminal by the Vatican, forcing him to abandon his previous affiliations. He later associated himself with Fallen Angel forces, continuing his activities as a rogue combatant. Overall, Freed Sellzen is characterized by his instability, combat-driven mindset, and detachment from institutional control, making him a disruptive and dangerous figure within the broader conflict between factions.

Creuserey Asmodeus was one of the three leaders of the Old Satan Faction and a descendant of the original Asmodeus. Creuserey strongly opposed the current leadership of the Underworld, believing that the modern Satans did not properly represent the legacy of the original rulers. He viewed himself and others of similar lineage as the rightful successors, often referring to himself as a “true” representative of that legacy. He was known for his extreme pride and rigid beliefs, placing great importance on heritage and status. This perspective led him to reject the current system of governance and the cooperative approach taken by figures such as Sirzechs Lucifer, particularly regarding alliances with other factions. Creuserey’s outlook was defined by a desire to reshape the Underworld according to his own ideals, favoring a return to older traditions rather than adapting to changing circumstances. In pursuing this goal, he aligned with others who shared similar views, seeking to challenge the existing order and replace it with their own leadership. However, his strong confidence in his beliefs often prevented him from recognizing opposing viewpoints or his own limitations. This rigidity became a significant weakness, especially when facing individuals who possessed both greater power and a more balanced perspective. Overall, Creuserey Asmodeus is characterized by his unyielding ideology, strong sense of lineage, and resistance to change, representing a faction that sought to restore what they believed to be the original structure of the Underworld.

Sairaorg Bael is the heir of the Bael Clan, one of the most prominent noble families in the Underworld. He is the eldest son of Lord Bael and the only child of Misla Bael, as well as the older half-brother of Magdaran Bael. He is also a relative of Rias Gremory and Sirzechs Lucifer. Prior to his defeat by Issei Hyoudou, he was widely regarded as one of the strongest young Devils. He is the wielder of Regulus Nemea, a Longinus-class Sacred Gear. Sairaorg is known for his calm, disciplined, and honorable personality. He approaches both allies and opponents with respect, valuing strength, effort, and determination. He actively seeks out strong opponents as a way to improve himself, demonstrating a deep commitment to personal growth. Despite his strength, Sairaorg is also kind and compassionate, showing understanding and fairness even toward those who are marginalized or treated unfairly. His experiences with discrimination during his upbringing shaped his open-minded worldview, leading him to reject the idea of judging others based on lineage or status. This perspective is reflected in his peerage, which is composed of individuals who have been overlooked or underestimated by others. Sairaorg believes in creating opportunities based on ability and effort rather than background. He is deeply committed to his long-term goal of building an Underworld where individuals are judged by their actions and dedication, rather than heritage. His determination is especially evident in his efforts to protect important institutions and maintain stability for future generations. Sairaorg takes great pride in his strength, particularly because it was achieved through hard work and perseverance rather than natural talent. He values self-improvement and maintains a strong sense of personal integrity. Overall, Sairaorg Bael is defined by his discipline, fairness, determination, and sense of responsibility, standing as a figure who seeks to lead through effort.

Cao Cao is a descendant of the historical Cao Cao and the former leader of the Khaos Brigade’s Hero Faction. He is the wielder of the True Longinus, regarded as the first and most powerful Sacred Gear. Following Sun Wukong stepping down from his role, Cao Cao later becomes a vanguard under Indra. Cao Cao is known for his strong charisma and strategic thinking, allowing him to gather and lead individuals with Sacred Gears into a unified group. He places great importance on human potential and believes that individuals with unique abilities should strive to reach their limits. His outlook is heavily influenced by his heritage, leading him to see himself as someone with a significant role in shaping the balance between humans and supernatural beings. He possesses a high level of confidence in his own abilities, often approaching challenges with the belief that he can overcome even the strongest opponents. At times, this confidence develops into overconfidence, which can affect his judgment in critical moments. He may become visibly frustrated when situations do not unfold as expected. Despite this, Cao Cao is capable of recognizing strength and potential in others, showing respect toward individuals he considers worthy, including Issei Hyoudou, Vali Lucifer, and Azazel. He is also thoughtful, often analyzing situations deeply when outcomes differ from his expectations. Cao Cao places importance on the concept of purpose and destiny, believing that encounters between powerful individuals occur for meaningful reasons. Over time, he begins to question his own role and the true meaning of being a “hero,” especially after reflecting on his past actions. Following these reflections, Cao Cao undergoes noticeable personal growth, becoming more cooperative and willing to work alongside former adversaries when facing larger threats. He contributes to efforts aimed at maintaining stability and protecting others.

Millicas Gremory is the heir apparent to the Gremory Clan, following his aunt Rias Gremory. He is the son of Sirzechs Lucifer and Grayfia Lucifuge, and the grandson of Zeoticus Gremory and Venelana Gremory. Although his father held the title of Lucifer as one of the Four Great Satans, that position was not hereditary. As a result, Millicas carries the Gremory family name and is recognized as a future leader within that lineage. Millicas is known for being a polite, respectful, and well-mannered child. Despite his young age, he demonstrates a notable level of responsibility and maturity, already thinking ahead about his future role and the structure of his own peerage. He prefers to be addressed simply as “Millicas” by those close to him, showing a humble and approachable attitude rather than insisting on formal titles. Born only a few years before the beginning of the main story, Millicas represents the next generation of the Gremory Clan, carrying both its legacy and expectations while maintaining a grounded and thoughtful personality.

Zeoticus Gremory (ジオティクス・グレモリー, Jiotikusu Guremorī) is the current Head of the Gremory Clan. He is the father of Rias Gremory and Sirzechs Lucifer, the grandfather of Millicas Gremory, and the husband of Venelana Gremory. Zeoticus is known for his kind, warm, and easygoing personality, reflecting the affectionate nature associated with the Gremory family. He is approachable and friendly, often creating a relaxed atmosphere around those close to him. Similar to his son Sirzechs, Zeoticus has a laid-back and playful side. He enjoys lighthearted activities, including dressing up as the Gremory Clan’s mascot, “Gomorin,” and entertaining others. These moments highlight his informal and humorous nature, though they occasionally lead to him being reprimanded within his household. Despite his relaxed demeanor, Zeoticus is a responsible and capable leader. During the Devil Civil War, he and the Gremory Clan supported the Anti-Satan Faction in order to prevent further large-scale conflict, demonstrating his commitment to stability and peace. As the head of his clan, Zeoticus also handles important political and family decisions. One notable example is arranging a future marriage alliance between his daughter Rias and the Phenex Clan, reflecting the importance of maintaining noble ties within Devil society. Outside of his formal duties, Zeoticus has shown an interest in the human world, even developing his cooking skills there. This interest reflects his open-mindedness and willingness to engage with different cultures. Overall, Zeoticus Gremory is characterized by his balance of kindness, humor, and leadership, serving as both a caring family figure and a dependable head of one of the Underworld’s most prominent clans.

Sirzechs Lucifer, formerly known as Sirzechs Gremory, is one of the most powerful Devils in the Underworld and the former Satan Lucifer, who oversaw Domestic Affairs prior to the events of the Evil Dragon War. He is the eldest child of Zeoticus Gremory and Venelana Gremory, the older brother of Rias Gremory, the husband of Grayfia Lucifuge, and the father of Millicas Gremory. Known as the Crimson Satan, he once led the Four Great Satans and commanded one of the strongest peerages in the Underworld. Sirzechs is widely recognized for his kind, compassionate, and approachable nature. He prefers resolving conflicts through discussion rather than force and consistently prioritizes the well-being of others. Despite his immense power and status, he remains humble and considerate in his interactions. He also has a laid-back and relaxed personality, often approaching situations at his own pace. This occasionally puts him at odds with his more disciplined household, creating lighthearted moments within his family. However, when necessary, Sirzechs can become serious and focused, revealing the full extent of his authority and strength in critical situations. Sirzechs possesses a strong sense of responsibility and self-sacrifice. In his youth, he took part in the Devil Civil War after witnessing unjust loss of innocent lives, driven by a desire to prevent further tragedy. Later, during the crisis involving Trihexa, he chose to remain in a prolonged battle to protect the world, fully aware that it would separate him from his family for an extended period. This decision highlights his dedication to safeguarding others, even at great personal cost. Within his family, Sirzechs is deeply devoted and protective. He shows strong care for his younger sister Rias and takes his role as a father seriously, supporting and encouraging his son. At the same time, he has a playful and lighthearted side, enjoying simple activities with his family and showed an more relaxed attitude.