Red Nova

The Crimson Devil, whose true name is Scar-Red Nova, is the last and strongest of the Earthbound Immortals. It is known to be a remorselessly brutal demon. Apparently, it was so brutal, that the Dark Signers did not dare attempt to harness its power. It will comply to one who wields the state of a "Burning Soul", although there's apparently some complication to its legend.

Biography
In its true form, it single-handedly fought against the Crimson Dragon 5,000 years before the other Earthbound Immortals and lost. The Crimson Devil has a fire demon servant, the Familiar of the Crimson Devil, who plans to offer Jack Atlas' soul as a sacrifice, and give his body to Scar-Red Nova, to awaken the Crimson Devil from its 10,000-year slumber. It is said to be associated with the serpent Nazca Line.