Alex getting Isaac ( a son) instead of Mirall and neglecting him because Alex wanted a daughter could explain why Isaac hate Alex so much
New support to my claim: expect for hairstyle and eye color, his face look the same as Alex (MC) in Devotion, so I guess he took this from his dad while the hair and eye from mom? although to be honest I think it's just because whatever platform you use to create these character's apperance lack of options since most female charater have the very same stance and Alex Isaac have it too. (plus if there is a character creator you use pleas tell me the name I love the artstyle)