SPOILER
I read this somewhere but he's not the real anastacius, I mean the real one is already dead. Someone's inside his body and that's the guy that Lucas met when he's still in the tower.
Yes his not the real one but his is also still one of clauds brothers who was brought to lucas and Lucas refused to teach him for being weak and this is just a theory here but I believe he found some other guy to teach him but that person ended up being a dark magic user and taught him. So I think that's what his flash backs were about also yes I know his beef isn't with claude but with Lucas but damn that's a long way to go just to prove some dumb shit like that
i don’t think anastacius is fully dead tho. looking back at s2, anastacius was still in control of his body and bonds more with jeanette. he and mr. white doggie even talked abt wether he’ll reveal that he is jeanette’s dad to her. and even here in season 3, he have flashbacks when he was younger WHERE aethernitas (the “great” emperor obsessed w lucas) had been starting to brainwash him and they communicate. but rn yeah aethernitas probs took over anastacius’ body already. that happened that time when anastacius was trying to brain wash white doggie but failed and then the center of his eyes gleamed red from that point on. that’s the sign the it’s aethernitas already.
SORRY LUCK I'M TRYING TO BE LOYAL BUT THIS MOFO NACHT JOIN THE PICTURE SO YEAH BOTH OF YOU CAN HAVE ME ANYWAY (●'◡'●)ノ