This series hides a lot of hints behind the suspension of disbelief of the readers. So a lot of weird behaviours in the real world that are usually ignored by readers in japanese media,are still weird in the world of this story.
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How is the MC the rapist?
He did what he thought was a curse that would make her suffer endless pain. Not that she would get horny and attack him.
And after he spent years in coma, it was her that attacked him AGAIN and put the horny tatoo on him and it's mostly her using it to make him have...