I think that the Skull Sorcerer might be Cole’s mom because if you have seen the official season trailer Cole finds a necklace that belonged to Cole’s and I do not think whatever happened to her is as bad as Cole and his dad think that and how else could the thing that Cole spots in his room get Cole’s necklace also here is the link for the trailer if has not seen it yet https://youtu.be/U0t0tbcPCCE