I don't think they have the same mom. Claude might have been the child of a mistress while his brother was the child of the Empress.
Also, is the daughter in her father’s body/head/memory/childhood?
The moment Athanasius changed was the moment he was influenced by Aeternitas. Aeternitas brainwashed him saying something like he's being mocked and his family's looking down at him that's why he's always angry at Claude and when he succeeded the throne he killed Claude's mom and was also about to kill Claude but was killed instead.
I’m really confused. So what happened betwen him amd his brother? Did his brother kill their mom? Did the lom only love one son? I’m so confuused