Tien
Tien is a 3-eyed alien that lives on Earth. He is much more powerful than his friends Yamcha, Chouzu, and Krillin although he was trained by King Kai with them when they died against Nappa. He knows many techniques but they're mostly little parlor tricks. He doesn't do much in the series to make a difference. He does fight but basically he justs get beat up. In the GT series, Tien and his friends, because of their low power levels, serve no purpose and will gradually just fade away.