Shippo is a cute, little 'Kitsune' fox demon, and is one of the main 6 prognostics of the Inuyasha series. Shippo was the first one to join Inuyasha and Kagome's group. Shippo met the group when he stole their 'Shikon' shards, to become a stronger demon (duh) and avenge his father, whom had been killed by the thunder brothers. Kagome convinced Inuyasha to help Shippo and fight the thunder bros, this resulted in Kagome being kidnapped by hiten and held prisoner. She is then rescued by Inuyasha and Shippo, were Shippo's fathers fox spirit protects Kagome and the little kitsune. The battle ends with both of the thunder brothers dead, and Shippo left with no were to go, but Kagome convinces Inuyasha to allow him to come along. His role in the series stays (pretty much) the same, his role in battles is minimal, but his individual strengths (shape shifting, fox fire ect.) make him a key role in the team.
Inuyasha: Shippo assumes the little brother role to Inuyasha, the typical prank pulling, shape changing annoyance, but they do really care for each other
Kagome: Shippo is very close to Kagome and is her feudal Sota (her little brother), she always defends him when Inuyasha 'picks on him', and Shippo is quick to take Kagome's side in an argument
Miroku: they don't interact as much as some of the other characters but when they do it is as friends and comrades
Sango: Shippo is also some what of a little brother to Sango in the replacement of her brother Kohaku whom was controlled by Naraku for the series majority
Kirara (Key-la-la): the two are very close, being the only to full demons and fire users of the group they are very close friends, and some even expect that there is a small romantic link between the two, even though Shippo is a fox and Kirara is a cat