Ougon No Keikenchi

The conquest story of the final boss protagonist begins here!

“Boot Hour, Shoot Curse” is a VRMMORPG that has no concept of levels or professions. Instead, players must farm experience points to gain new skills and increase their status.
Rare, a girl who participated in the closed beta test, has acquired the hidden skill “Subordinate”, which allows her to turn NPCs into her subordinates. The skill also transfers the experience points gained by the subordinates to Rare.

She used the skill to gradually add new NPCs she encountered to her party. As a result of the unprecedented amount of experience gained from her minions, she was able to evolve into a Demon Lord.