Shinsen

was a monk who sealed Entei and Rengokuki in a cave years ago. When Kagura and the Infant find him they ultimately kill him but not before he splits the Infant in two with his spiritual powers.

Manga vs. Anime

 * In the manga, he was not given a name.

Media

 * Chapter 293
 * Chapter 294

Anime

 * Episode 141
 * Episode 142

Shinsen Shinsen 神泉