Little Aiden.
That's what Cassie called Aiden, the first time they met. It was when she was still seven years old and Aiden was fifteen. Cassie was quite short compare to the other watchdogs in the Matautia mansion at that time.
So, Aiden never believed that Cassie was capable of doing such things like fighting and some other exercise. When Cassie grew taller, she approached Aiden and invited him to watch her performance inside their gym.
Aiden never wanted to go, but Cassie was persistent and the latter just gave in and went to her performance. It was when Aiden found out how strong and protective Cassie was.
He was even complaining at that time because his father asked him to join the performance and Aiden repeatedly said no, but what could he do? It was already Master Evon who told him to join.