Could be his other grandpa, I.e. maternal/paternal
Could be his other grandpa, I.e. maternal/paternal Wait, I’m not sure on Wiccan’s comic origin. He’s Scarlet Witch’s son, but is his dad anyone in particular? Was he made by SW like in Wandavision?
His father is Vision, that would make Ultron his grandpa. Again, does fit with his claim.