Devoré todo y me convertí en dragón

A lazy office worker is reborn as a worthless koi at the bottom of the monster world. With a Devouring Evolution System and ridiculous luck, he eats his way from trash fish to dragon. He crushes bloodline snobs, rules the banquet, and rewrites the fate of the lake. But when the throne is his… can a former slacker stop pretending he doesn't care?