Satori

The beast is large, similar in size to Gamabunta and the Eight-Tails, with large wings. It is headless, with bones potruding from the mouth on its chest and is covered in black feathers. It also has a long thin tail, and its hands and feet are clawed and sickly thin to the point where it looks almost bone-like with skin attached.

According to Gamabunta, the Box of Ultimate Bliss "brings forth", "actuates", and "ends" with Satori. Beyond that, like the Box, Satori's history is overall a mystery. Little is known about Satori except that it has been around since the time of the Sage of the Six Paths and that Satori is merely a puppet of the Box. A person who enters the box and comes back out will become the host of Satori, gaining the demon's powers while having their mind corrupted, and Satori will proceed to throw victims into the box.