Sir Aaron is a legendary hero known as the Hero of the Wave in Lucario and the Mystery of Mew. In the movie, two armies are about to clash and the kingdom will fall into darkness. Sir Aaron journeyed to the Tree of Beginning to find Mew and help him save the kingdom. His close friend, Lucario, wanted to help to, but Sir Aaron threw the staff in front of him and sealed him inside. Sir Aaron managed to find Mew and used up all of his Aura to make Mew powerful enough to activate the Tree of Beginning. Before he died, he sent Lucario a message and begged him to forgive him for what he did because if he didn't seal him in the staff, he knew that Lucario would end up in the same exact fate and he bid he lifelong friend farewell.