Fallow Crown - Weak to Strong OP MC LitRPG (BOOK 1). Dungeon Chronicles, #1

In a world where the System ranks every living soul, Sevik Haejong is the only prince who registers as nothing. Twenty-four years of empty stat screens. Twenty-four years of dashes where numbers should be. The seventh son of a dying emperor, invisible to a court that measures worth in cultivation rank, ignored by brothers who stopped noticing him before he learned to stop caring. Then the floor beneath his bed begins to glow.
The Pale Root, a sealed dungeon built on the bones of six thousand murdered cultivators, has been quietly reshaping his body since birth. His empty meridians were never broken. They were reformatted. And now the dungeon is delivering the stolen skills of the dead directly into his veins. Each skill makes him stronger. Each skill makes him less human. The court is watching. His brothers are circling.
A councillor is building a file. And somewhere beneath the palace, a seal that has held for three centuries is starting to crack. Sevik has one choice: descend into the dungeon that made him, or wait for it to consume everything above. He descends.