Yoriichi

Yoriichi was born with a natural affinity for swordsmanship, possessing the "Demon Slayer Mark" and the "Transparent World" from birth. He revolutionized combat by creating Sun Breathing, the origin of all other styles. Despite his immense power, he lived a humble, sorrowful life, marked by his twin brother’s descent into demonhood and his inability to defeat Muzan Kibutsuji permanently. He remains the most formidable figure in the series, standing as the only one Muzan truly feared.