Kakarotto/Son Gokou:

Kakarotto, a low leveled Saiyajin was sent to Earth at birth, by his father Bardock, to destroy it. After arriving on Earth Kakarotto was found and renamed Son Gokou, by an old man, Son Gohan. Gokou, was at first destined to be evil because of his Saiyajin blood but was able to change due to a cranial injury he received when young. Gohan (who Gokou now called Grandfather), later trained Gokou to be a skillful fighter. However Gohan was killed by Gokou himself in an accident when Gokou transformed into an Oozaru when the moon was full. After Gohan's death, Gokou grew up to be powerful and gained the title, "The Strongest Man in the World". Later on in Gokou's life, he becomes the first person to reach Super Saiyajin Levels 1, 3, and 4. Eventually Gokou marries Chi Chi, a human, and has 2 half-Saiyajin children...Son Gohan (named after his Grandfather) and Son Goten.