I went down to the prison in Arx, found some Red Magisters there, a certain Magister Ristrum by name was jailed together with a female Red Magister. I spoke to this guy, questioned him, he claimed to be the brother of Delorus, poor guy, he died with Alexandar, anyway this brother of his told me something about the Whites and then he died? It looked like the other Red killed him, but I'm not sure, I didn't exactly pay attention, he walked towards the bars and was dead in an instant. Is he supposed to die for treason, or was this a bug? I'm not going to load the save before speaking to him, he won't be of use anyway, but I find it strange, that she could kill him for sharing some info with us. After all, he was kinda positive about it, like may we find the Whites, so they could end us, something like that he said. He was actually helping them to get rid of us, if nothing else. If that's seen as treachery, well.
