The Kite Rune is made for shuriken and dart-type weapon users and cannot be attached to anyone else. With it, they can alternatively attack several enemies on screen by command, though the damage will be halved at least. But in case of large enemy groups and first strikes the outcome may be an advantage in terms of added damage.
In games the Kite Rune takes place - Suikoden II, III and V - it is a common item and sold in shops. Look for crystals in Greenhill, Caleria and Rainwall for instance. If you happen to fight Faylon and Faylen on Ranro Mountain, a Kite crystal will be granted to you as well. - Celes