Piccolo

Piccolo (ピッコロ・ジュニア, Pikkoro Junia), is the Namekian reincarnation and final son of the original King Piccolo as well as the final villain in the first Dragon Ball series, and a protagonist in the Dragon Ball Z and the Dragon Ball GT series. He was born to avenge his father's death at the hands of Goku. According to Grand Elder Guru, Piccolo, along with Kami and King Piccolo, are part of the Dragon Clan, who were the original creators of the Dragon Balls.
After his narrow defeat against Goku, Piccolo is soon forced to form an, at first, uneasy alliance with Goku and his friends against newer, more dangerous threats. Thus, he and Goku kick off the formation of the Z Fighters. Also, out of necessity he also takes it upon himself to train Goku's young son Gohan, forming a powerful bond which ultimately redeems him when he sacrifices himself to save the child's life from Nappa. After his resurrection he fully joins Goku and the others in their struggles against ever more powerful villains on Planet Namek and Earth. As the story progresses, his role shifts from warrior to mentor. He is one of the most intelligent characters in the series, retaining King Piccolo's tactical genius, and later gaining Kami's great wisdom after fusing with the old Guardian.

Piccolo is originally villainous, much like his father. When battling Goku in the 23rd World Martial Arts Tournament, he shows almost no mercy and no regard for his opponent, breaking all of Goku's limbs while laughing. Despite this, when he and Goku team up to battle Raditz, Piccolo does begin to show more honor during battle, even commemorating Goku on his noble sacrifice. After he trains and befriends Goku's young son, Gohan, Piccolo's heart and motives quickly begin to change. During the battle with Nappa, Piccolo goes as far as to sacrifice his life to save Gohan, stating how his friendship and love had changed him forever. Piccolo has stated that Gohan was the first person to see him not as a monster and was proud to call him his friend. Upon his return during the battle with Frieza on Planet Namek and after fusing with the
Namekian warrior Nail, Piccolo fights for the honor of his people and to save the innocent. Years later, during the Androids and Cell arc, Piccolo still does retain a bit of ruthlessness and cockiness, but once he fuses with Kami, all traces of evil and hate disappear, and Piccolo is completely reborn as a pure soul.

Even after merging with Kami, Piccolo remains a loner, preferring to stand apart from others. He has little to say unless it involves battle, and doesn't seem to understand the concept of romance. (He often sees "mushy stuff" as disgusting).