Nana

Thirdy years ago, mysterious spatial tears known as Gates opened across the globe, connecting human civilization to lethal dungeons filled with monstrous beasts. To combat this crisis, humanity relies on Adventurers ranked from E to National based on their combat capability a d Nana is one of them, standing at the A rank, she is a young prodigy that became an adventurer 6 months ago, and she's now standing at rank B.