Doomsday; I Am Fighting Monsters and Upgrading

Wang Yu traveled through time and became an ordinary high school student whose parents both died. It wasn't long before he traveled back through time. Just when he was full of passion and wanted to make a splash in this strange world. He saw a mosquito that had reached his fist, and compared the strengths of both sides, he suddenly thought that perhaps he should value peace. After all, the time travelers like us are from flower growers, so we still need to pay attention to necessary etiquette. However, the other party was really bullying him too much, and he had no choice but to silently raise the knife in his hand and strike with one blow. Since I can't be ordinary in this apocalyptic world, then I will fight for eternal peace! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.