Piccolo is a fighter from Dragon Ball. He initially started off as a villain in Dragon Ball but since Dragon Ball Z he has become a hero and ally to Goku and the civilians of Earth.
At first, Piccolo was cruel and vicious to the Earthlings and others. He later began to show some respect for Goku and his allies in his battles against Frieza's men. In fact, Piccolo has shown some respects for his former enemies and have acknowledge them as his comrades on many occasions. He even has great respects for Goku's family and friends like Gohan, Bulma, and Krillin. Ever since his redemption, Piccolo has shown great loyalty to them.
As a formidable Namekian, Piccolo has an immense amount of strength and power. He has the ability to fly like most fighters in Dragon Ball. Combined with his speed and superhuman strength, Piccolo is capable of tearing apart his enemies. He was strong enough to fight powerful opponents such as Frieza, Android 17, Cell, and Majin Buu. Even though, Piccolo loses in the majority of his battles, he was still capable of lasting long enough of to put up a threat against these opponents. In his battle against Imperfect Cell, Piccolo was strong enough to severely injure him on some occasions.
Piccolo has displayed a variety of weaknesses in his battles. If Piccolo loses a limb in battle, it would take time for it to regenerate. While the limb regenerates, Piccolo will be handicapped for the moment. He will not be able to even shoot energy beams at his targets for a moment, if he was to lose an arm in battle. In his battle against Imperfect Cell, he was severely weakened when the latter absorbed energy from his body and was nearly killed in the process.