Why did Yang respect this faggot so much?
He artificially prolonged the war for no other reason than his own greed.
Reinhard isn't even that well written, they never give a reason why he's autistic and unable to make friends despite being incredibly charismatic and handsome
Oberstine got it right
That's usually the features of psychopaths. They can be handsome and charismatic to deceive but are loners on the inside.
There wasn't anyone he could trust.
There were emperors in real history who became mad for the extreme paranoia they suffered. There was literally no one in which they could trust.