I think the Psi monks tried to kill him, if you read your history you'll know Regant suposedly fell to an illness, staight after the PSI monks took control, I believe they used their powers to kill him the main reason for them to do this is that Regant is the sun of Thor who was Crahns mortal enemy and since we have the Crahn Sect I think it's safe to say they didn't like Thor one bit, I think they used Regant to get rid of Ceres and then tired to get rid of him. Perhaps Regant is partly insane because of the damage done by the PSI Monks or perhaps simply hates all humans now.

Some history I would like to know is about the dome, we know Regant installed an over seer so to speak, but what happened after that? Why did the dome go to war with NC, is it because Regant was userpt, or did the people of the dome rise up and kill their over seer then set about avenging Ceres? It is also noted that the dome bombed the canyon and now they have the twilight guardians in their home, are the people of the dome now prisoners? Or have they decided it's better to have drug dealers, thugs and terriorists amoung their citizens? Not that the corporations of neocron are any better... i do ramble on