pro cannibalism individual

1) Why did Utsugi cut off Hajime's lower body and eat it

He did not Literally Eat Hatsutori's lower half. The melting started because of Seodore. (Record 5)

And then Utsugi shows up and fights off Seodore and then Takes Half of Hajime's Body. (I'm not screenshotting every line because I'll hit the image limit, so please rewatch the full scene for more context).

And you can see this scene again in Record 7, in Utsugi's version.

Hatsutori is dying. Utsugi wants more than anything to stop it. So he does!

2) For what reason did he hate Minoru Harada?

He didn't hate Minoru. the screenshots here are from records 6 and 7. I can't get everything obviously but I think rewatching might help! There are a lot of good scenes between them.

he gets told very very clearly that everything will end in ruin if Minoru stays. He likes minoru! he does! but that's a part of the problem.

He does everything he can to get Minoru to leave, and to stay away. He can't tell him why. He can't explain it. Because to explain is to burden Minoru with the curse of knowledge that Utsugi has no idea how to cope with. And he does, even still, try to reach out for help. He tries to ask Minoru for help and Minoru FUMBLED. But they don't hate each other.

They fight, and they argue and disagree, but they don't hate each other.

I can't screenshot every line like this but he makes it pretty clear, i think.

I haven't included the entire record 7 ending monologue here but it's really good!!

3) Did Hajime's condition worsen because he was a fragment or was it related to his mental state?

His powers react to his mental state. Is this what you were thinking about? His physical condition of missing half his body is because of the fight in 1999.

4) This had something to do with the cell inhibitor, but why did Haruki tell Reiji not to use his power towards the end of route S?

This was ambiguous. my general interpretation was that if they used their powers, theyd be more closely connected to Hatsutori, so when the belfry rang, they'd die too. (these screenshots are from S, not S+).