Game Chishiki de Saikyou ni Natta Mob Heishi wa, Shin no Jitsuryoku wo Kakushitai

Silva wakes up one day to find that he has been reborn as a minor background soldier inside the very game he obsessively played in his previous life. Determined to use what he remembers about the world to keep himself alive, he also tries to suppress his actual abilities so the established scenario can play out untouched. That plan unravels when he unexpectedly cuts down a powerful demon that even the designated hero struggles against, and the feat unfolds right in front of his favorite in-game heroine. From there, rumors of his real combat power begin to spread, and the fantasy follows a hidden veteran forced to fight openly to defend the character he most wants to protect.