Global Cataclysm: I'm Fighting the Supernatural for Human Heads

After the blood rain, the bizarre descended.

In his previous life, Wei Yang was thrown out of his room by the couple he shared an apartment with and killed by a bizarre entity. Reborn, he gains an evil System that makes him stronger with every life he takes.

He kills his enemies with his own hands. Afterwards, he plans to leave before the bizarre entities arrive, only to find that they've sealed off the area ahead of time.

To survive, he makes a crazy decision: kill all the other residents and face the bizarre entities himself!

(Later on, the protagonist will be like a Hannibal-type character, blending into society and dealing with the people who make everyone sick.)