Kanon is a Merc (mercenary who takes jobs for money, as well as hunts down demons). She's antisocial, and usually doesn't work with others. Most of the game has her keeping her distance from the rest of the party.
When you first meet her, Kanon hires the group to aid her in an exorcism of the demons of Slayheim Castle. In truth, the demon she wanted to exercise was the one inside of Ashley Winchester (the hero). After losing the battle, she flees. You fight her two more times, in the emulator zone and in the abandoned mine. After the mine, she decides to join the group, in return for being able to kill Ashley the second he succumbs to Lord Blazer.
Kanon is actually named Aisha Bernadett. When she was small, her mother and the rest of the town were killed by attacking demons. Ever since, she has been forced to use a bionic arm in place of her left one--which had died. After that incident, she threw away her name and past in order to become a Merc and slay demons for revenge.
Kanon is a relation to the Valeria family (but it is unknown exactly how close their blood is). She is a descendent of Anastasia, The Sword Magess. Thus, she believes that she should become a hero.
At one point, Ashley succumbs to Lord Blazer. He asks Kanon to kill him and destroy the demon for good. But for some reason, she is unable to lift her blade. It was lucky that his feelings for Marina were still present. After a close encounter with the part of her that is still Aisha Bernadett while in Raypoint Muse, Kanon realizes that she wasn't looking for fame in that sense. She was longing to have friends who cared about her, something she lost so long ago. Thus Kanon found that she'd had what she'd been searching for ever since she joined up with the others, and the real reason she couldn't slay Ashley on that day.
She can learn new techniques by practicing old ones.
There's a built in radar inside Kanon's eye.
Somehow, Irving knows her true name even before she tells him, which may say that they're related on a real close level.
Her tools are a Hookshot, Roller Skates, & Jumping Boots.