Omen is a demon herald of Gargos and the secondary antagonist in Killer Instinct 2013. He is a bonus character in Season 2, and is the dark spirit that had possessed the warrior Jago, turning him into Shadow Jago. He is a loyal servant of the astral deity Gargos, and has been given the special duty of preparing the world for the return of his master.
He is the only character of Season 2 to not have his own Rivals Mode story - however, he does make an appearance in several others' as an opponent. In Season 3, several other Omens appear as servants of Gargos in Shadow Lordsmode, and defeating each one will weaken Gargos in the coming battle.
Omen's relatively simple design bears a resemblance to Cinder from the original Killer Instinct. His appearance is that of a human silhouette, consisting of a strange, shadowy-blue fog, transitioning into a bright, white color around his face, fingers, and toes. Electricity seems to indefinitely crackle along his body. When attacking, the high speeds create thin, white streaks that trail behind his fingers and toes. Inside of his thoracic cavity is a ribcage-like structure composed of tubes simliar to blood vessels, and, occasionally, a deep blue image of a human heart flashes from deep inside. These "blood vessels" extend from his chest and run down his arms and legs, similarly to a skeleton. His face is similar in appearance to a traditional, Japanese oni mask, with two horns and a despondent expression. When flying and performing his signature Demonic Despair attack, he manifests wings similar to those of Gargos, his master.
And he is reprised by Chase Ashbaker in the English dub and his Japanese voice is unknown.