Gulph's Power and Love

In the book Crown of Three Gulph one of the triplets has figured out his power. What I didn't know is that Gulph , Elodie and Tarlan's mother was a witch. So it confused me a little when Elodie had the power to see dead people and Tarlan could talk to animals. However I was really confused because I was thinking what is Gulph's power? Does he not have one? However Gulph's power is that he can turn invisible! He doesn't know how to activate it though. What I thought was a interesting part in the book is when Nymus was getting attacked by his undead father Brutan and Gulph rushed over and tries to help him. However Gulph doesn't get there in time to save Nymus and he gets stabbed in the stomach. Gulph comes rushing over to help and stay by Nymus's side and Nymus doesn't understand why. Gulph did it because Nymus was his brother well step brother. Also even though Nymus has turned into a monster Gulph still cares for him helps him the best he can. I think that was an amazing moment in the story.