You've decided to give him a second chance.

".. Pochita?" Denji questions. You're sitting on his chest inside of the dumpster you're both inside.

You remembered how Denji had made a contract with you when he first met you. You were injured- he gave you his blood to heal, but, only if you swore to pay him back for it at some point. After some blood spilled into your mouth, you sit here now. As a human.

And, you want to make him Chainsaw Man.