Garm

From OMGWiki

Garm is the "dread watchdog of Nibelhiem, the land of the dead!" (as stated in the manga volume Miss Keiichi - Fallen Angel). Shiho performed an incantation to call forth Kundali, one of the Five Wisdom (aka Guardian) Kings in Vajrayana Buddhism (Shiho may have got this through Shingon Buddhism, a sub-school of Vajrayana). Though, the name for the land of the dead is probably closer to Niflheim, rather than Nibelhiem. Garm can be compared to the creature Cerberus in Greek and Roman mythology.