Fire and Ice

Fire and Ice are the names of the two swords used by Obsidian the master of the Assassins Guild. They were the first weapons created out of fire-forged steel and frost-forged steel as they were stolen from Ash's father by Ghost defender of phase so that it could be traded for Obsidian's granddaughter, Luna, for her unique ability to contact the Lunar spirits. It is currently still in the hands of Obsidian and is the main reason why Ghost and Ash dislike each other.