And WHY there is no BARA fanart of him? Get your s--- together Undertale Fan Artists!

Notes:

Tumblr Source

He looks like Hellboy to me

His name is indeed Oni

Oni
This monster will complain about the sheer amount of puzzles in the Underground, claiming that you can hardly go anywhere without being buried in puzzles. They express joy at the thought of going to the surface, and hope that there are not as many puzzles there.
- Undertale Wiki

SPEAKING OF BARA!
DId you know that the Royal Guards' Sprites are named with the word "bara" in the games' files,
Toby REALLY know his s---