blood raven is a spectator with his own hidden agenda(a targaryarn 1st) nd in my opinion u er trying to force ur mc to be dark for no reason....yy would he hate his father for been honorable all he has to is fo things his own way....
blood raven was last known person to have dark sister and if he trains mc then mc has chance for a valyrean sword but either way the magic system of planetos is based in ritual magic of sacrifice and recieve so a guide is needed unless you want to be possessed or accidentally do a white walker