System?

After betraying his girlfriend Meili, instead of the promised rewards, Lint was poisoned by the instigator and thrown into the slums with Meili. There, he was taken care of by the pregnant Meili, who was eventually forced into prostitution to earn for her family,as she was very pampered and did not have the necessary skills to make a living. Five years later, Witnessing the suffering of his family and accepting his uselessness, Lint contemplates ending it all. However, a mysterious entity, which called itself a system, offers him a deal: immense power to change their fate.
In exchange, he becomes something different. Now cursed with a monstrous transformation and an impossible task, he must decide between saving his family and preserving his humanity.

Note : images aren't mine