Arlin is a playable character in Atelier Iris: Eternal Mana and a mysterious swordsman who is out for revenge against Mull. No one seems to know much about him or his reasons behind this.
When Klein goes to Zeldalia for help, Arlin joins the party to seek out and destroy Mull. Although he stays with the party for a while, he eventually leaves to take on Mull by himself.
