Scarab

Scarab (スカラベ, "Sukarabe") is the spirit of ancient bugs and the guardian ghost of Nakht Pitrah.

About
These bugs were considered sacred by the ancient Egyptians, who thought the sun was moved by one of these insects as if we're one of their balls.

Oversouls and Attacks
Nakht can make his Over Soul with his guardian ghost while using his pyramid mask and uses the pyramid power to attract sunlight and recover Furyoku. The pyramid can also create a defensive barrier, even though Nakht couldn't use it to save himself because he was instantly killed.

Anime/Manga Difference
The Scarab never appears in the manga series or anime series. In the anime, Nakht's guardian ghost is a sphinx.