Eternal Guardian Oddyssey

Reincarnated in the world of anime, acquiring a system, having no responsibility other than thinning out 'monsters' in the [Dungeon], getting the opportunity to be overpowered and travel to other fictional worlds, and can do anything as you wish...

Are those things worthy of being an existence like Counter-Guardian from Nasuverse for eternity?

Well, our protagonist thought it was worth it...

At least, in the beginning...