Piccolo

Piccolo begins the series as an evil character. He is actually a second-generation Piccolo, the first having been the evil half of Kami and was destroyed by Goku after killing Krillin. The current Piccolo was spawned by the Demon Piccolo's egg, and is nearly the same as the previous Piccolo until he develops a bond with Gohan. Until that point in time Piccolo was intent on killing Goku and taking over the world, but his love for Gohan brings him over to the side of good, although he is never exactly kind to anyone other than Gohan.

Piccolo is a valuable asset to the Earth's team of warriors. He is incredbily strong and disciplined, and always pulls through in a tough situation. He also seems to be one of the only characters in the entire series who always seems to use their head in addition to knowing and understanding exactly what is going on.