After his father was killed by the 'Thunder Brothers' (his mother was never mentioned) he tried vainly to get revenge. He was stopped by Inuyasha and Kagome who later defeated the two brothers. He now travels with Inuyasha and Kagome and the other main characters.
It is generally thought that a 'Shippo' is someone of large physical strength or prensence, but not necessarily that intelligent. And will sometimes turn upon friends when bored.
Victim: Ow, mate you are being such a Shippo!