Kaiden Amethyst (アミシスト ケイデン Ameshisutu Kaiden) is the central protagonist of the story.
He is the second known person to be directly hit by an X-Meteor.
Kaiden has purple hair, an inborn trait akin to all Amethysts.
Kaiden is a rather cynical and pessimistic individual, as he never holds high expectations nor display any signs of surprise or shock at anything. He is very laid-back and careless, as he gives no importance to what others think of him or consequences that may be drawn from his acts. He usually invents names for people who refuse to give him their names, or anyone with an unusual name or name longer than two syllables. He also often massacres the names of others, either purposely to get on their nerves or simply because he disregarded their importance.
However, he is good hearted and is willing to help anyone who is in need, going as far as opposing the entire Alliance to save as many people as possible.