BioIppei is Sanpei's eldest brother and the strongest combatant of the ninja village. Ippei is the current chieftain of the Ninja Village and preceded Hanzo who retired.
Ippei defeated Kagetomo in a Pokémon battle and as a result he rescued Hanzo and during the village festival was pronounced the new chieftain.
Ippei's Greninja is Ippei's main Pokémon and strongest combatant of the ninja village. Kagetomo's Weavile was summoned to battle against Ippei's Greninja. Hanzo noted that in terms of speed and the power of their moves, they were evenly matched and perhaps Kagetomo's Weavile might be a bit stronger but Ippei had his brothers and the ninja villageres for support, something that Kagetomo didn't have. Ippei defeated Kagetomo in a Pokémon battle and as a result, Kagetomo realized he wasn't strong enough yet but he also had a change of heart.