Here's an outline of how it starts:

A story about revenge. It starts with a guy trying to kill himself and failing, but at that moment Momoka (who might be his sister) tried to killed herself too. He finds out that she was bullied by the same group that bullied him, and chases one of them down and forces her to undress and be violated just like she did to Momoka.

He says she killed his heart, and when he badly wants to get revenge his body turned into that of Momoka's and he killed the other girl. To be continued...

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Thank for the outline. What about the second part?

Base +5