Santemboss, more commonly known as 'Santa', is a spirit that possesses a book that Xisenin owns. Xisenin is well aware of this, and talks to the book often.
Santemboss looks like a brown hardcover book with many blank light yellow pages.
Santemboss can sense others around him, but, to communicate precisely, one must use a pen or writing utensil and write on the page currently opened. Santemboss cannot speak with sound, but instead talks through writing and drawing. When he does this, it looks as though an invisible hand is drawing it. Santemboss can suck people into his own dimension, as well as remove them from it. Santemboss can also teleport and open himself, and bring drawings to life, 3d or on the page.
Santemboss is maniacal and crazy, drawing disturbing pictures and stuff. He shows a liking of Tetris when he assaults Mario (who was zapped into the Santemension) with falling tetris blocks.
- It is unknown what the real book's title was, as Santemboss is a name given to the spirit that inhabits the book.
- It is possible that Santemboss can possess other things, as Xisenin is frequently shown drawing on his wrist, possibly communicating with Santemboss.