Fire was one of the four android creations of the Keeper. He had the ability to manipulate fire.
The Keeper was left by her makers on the Keeper's World to restore it after it was devastated in an ancient war. To assist with this task, and to fend of her loneliness, the Keeper created four nameless android helpers. One of these was an android in male form who could control fire, both creating and manipulating it.
During the Battle of The Keeper's World the androids sided with Princess Leia Organa, Luke Skywalker, C-3PO, and R2-D2 against a squad of Imperial Stormtroopers. During the battle Fire created a wall of flame with a mere gesture, frightening the Stormtroopers who had invaded the Keeper's Temple. He then led the Rebels to meet the Keeper herself.
Fire had the appearance of a human male with red hair that seemed to change in length and body like a flame. He was not immediately identifiable as a droid, save for his photoreceptors, which looked like a yellow light shining from black eye sockets.
Fire spoke the most of Keeper's android creations, and frequently took the role of leader. He was aware of the Galactic Empire, and had a distaste for Imperial Stormtroopers, to the point of being the first of the four androids to attack the Stormtroopers. He was loyal to the Keeper, but was willing to rely on his own judgment, overriding the Keeper's desire to be unknown when he felt the cause was worthy enough.
Through some unknown means Fire had complete mastery over his namesake element. He was able to both create fire at will, and also manipulate it as he wished, whether in ribbons of beautiful flame or as a wall of burning fire.