Son Goten

Goten is the second son, drawn as a smaller copy of his father down to the hair, and introduced in the last stretch of the manga. His childhood is the opposite of Gohan's. Nobody needs him to fight, so nobody drills him, and he turns Super Saiyan as a small child almost by accident because his mother wanted him to stop wasting energy on other things. The transformation that once cost a planet's worth of grief is now something a kid does to win a race.

Most of what he does he does with Trunks. The two of them learn the fusion dance from Goku, which requires mirrored poses performed in perfect time and fails ridiculously when a finger is out of place. Fused they become Gotenks, who is stronger than either and considerably more annoying than both, and who names his attacks while performing them.

The 悟 in his name is the same character his father and brother carry, and the ten is heaven. Toriyama put the pair of children in the final arc partly to hand the comedy somewhere while the adults dealt with the threat, and partly because Weekly Shonen Jump readers respond to characters their own age.