From Bulbapedia, the community-driven Pokémon encyclopedia.
Kagetomo (Japanese: カゲトモ Kagetomo) is a recurring character who first appeared in The Legend of the Ninja Hero!.
Kagetomo with his mask on
Kagetomo appeared in The Legend of the Ninja Hero! and A Festival of Decisions!. He was a former member of Ninja Village, having been an extremely competent ninja who was marked the most eligible to be crowned chief after Hanzo. However, due to his excessive thirst of power and self-assertion, he disagreed with Hanzo's ideas of using one's ninja power for the welfare of people and Pokémon. He was estranged from Hanzo and trained rigorously in exile. He returned, after some years, and abducted Hanzo, in order to use him as a hostage so that he could force the residents of the Ninja village to obey him as the new chief, instead of Ippei.
He was first seen coordinating the attack in the village alongside his partners Heidayu and the rest of Ninja Army.
Later, when the attack began, he personally attacked and captured the village elder in front of Sanpei, Shinobu, Ash and his friends.
He battled Ippei's Greninja, using a Weavile with excellent potential and showed a remarkable command over ninja tactics. However, in the end, Greninja emerged victorious after a hard-fought battle.
Realizing his mistake after receiving some pearls of wisdom from Hanzo, he decided to leave the Ninja Village in order to train harder, and focused his attention on exploring the true meaning of a ninja's life. Heidayu followed him, while Ippei waited for his return.
This listing is of Kagetomo's known Pokémon in the anime: