That's his stepmother if I'm not wrong but technically she is his rightful guardian hence he said the I'm your son line. His real mother was friends with the stepmother and father in the flash back and they seemed to be on an adventure together. The real mother is dead and I think she was the last of her family who had some kind of special power we don't know yet. His stepmother is from another well known family but from what's shown till now she doesn't contact them and they seem too mysterious and private. My guess is she left them because they were doing some sinister things and married the head of adenca to gain power. When vinchen got the mission she seemed to have already assumed he'll struggle because of what lies behind the mission hinting she knew her real family's involvement. So when the heir of herlam family came and called him nephew it showed that he was the stepmom's brother. I hope this clears up the confusion idk if I helped.
thank you so much!!!
yall are freaking out because he aged himself but im here asking myself what just happened i forgot everything about his mothers side and if she was "dead" or something