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
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....