The guy inside Simon, Kristian can't transform. He has no form. Maybe because the body was complicated, the body had no form. Neither his soul, nor Simon's body, nor that half-mermaid heart had a form to help Kritian get strong.
He was simply a mess.
Kristian actually didn't know that mermaid heart thing until he realised things after listening to the queen mother. He knew Simon had experienced strange things with Thomas that night. The nightmares, they were the things he had experienced in real life.
Kristian had lied a lot to Thomas. He never thought Thomas would ever find out he is not Simon. So it was bad. He never expected it, so he never thought about Thomas's reaction when he find out about things
After he saw Thomas crying, he understood. He had done the wrong thing.
He shouldn't have given hope to Thomas.
He shouldn't have talked with Thomas.
He shouldn't have let Thomas continue loving Simon.
