In Japanese mythology, Kagutsuchi was a god of fire who scorched his mother, Izanami, to death while being delivered. In a rage, his father Izanagi cut Kagutsuchi into eight pieces, from which were created other gods.
Shin Megami Tensei
In the Shin Megami Tensei series, Kagutsuchi's appearance remains true to his roots and is depicted as being scarred and surrounded by flame. His most recent appearance was in Devil Summoner 2: Raidou Kuzunoha vs. King Abaddon.
However, one exception is his characterization in Shin Megami Tensei: Nocturne. In it, Kagutsuchi's form is more akin to a sun, and effectively duplicates the moon phases seen in other Shin Megami Tensei games.
In the storyline, he acts as a barrier to test the will of the Reason bearer and is the final boss on most of the alignment paths.