Ninmenka

was a demon fruit tree which devoured souls of people and turned them into human faced fruit. Tōkajin used these to try and achieve immortality.

History
When Tōkajin waits for the time for him to be sage, he sees a Shikon jewel shard and later complains that it cannot be eaten, so he throws the shard behind him. However, he accidentally threw the shard into Ninmenka, the demon fruit tree. Ninmenka speaks behind Tōkajin, thanking him for the shard and asks him if he wanted to be a sage. Tōkajin answers yes, then Ninmenka orders Tōkajin to eat the human head peaches, in order to become a powerful sage. It was because of Tōkajin's shard that revived him and after a while a samurai had it shows that Tōkajin took Ninmenka's shard because Tōkajin was tired of Ninmenka's rude orders. Tōkajin later loses his shards of the Sacred Jewel after Kagome hits him with a sacred arrow, and the shards come flying into Ninmenka and the tree absorbs them. As Inuyasha and Tōkajin fell off a cliff to their doom, Ninmenka catches them with its roots. Ninmenka then devoured Tōkajin, and transformed itself into a large thorn root monster; the result was Touboku Ninmenka. Inuyasha then reverts back to his half-demon form when the sun rises, and he easily destroys Ninmenka.

Manga vs. Anime
The Ninmenka has the ability to speak in the anime, but does not in the manga. In the anime, the human faced fruit that Ninmenka bears have the appearance of peach-like fruit with small human faces, whereas in the manga the "fruit" that Ninmenka bears look like actual human heads.