For the legendary item, see
Omen is a canceled League of Legends Champion.
Omen was a quadruped demon-like creature which, as Tom 'Zileas' Cadwell explained in his GC Online talk 'Designers Are Humans Too--Causes of Poor Design Decisions', no one at Riot was sure if he was a melee or a ranged DPS character. This lack of both direction and excitement for the Champion caused him to remain in limbo for a while. Eventually, even though Omen was halfway through his development cycle, Riot realized he wasn't 'getting any better' and was ultimately scrapped and Riven was released in his place. Patch V184.108.40.206 had to be delayed due to Omen's cancelation in order to accommodate his replacement's release 
- Omen's development involved Rioters such as Brian 'FeralPony' Feeney (lead designer)  and Michael 'IronStylus' Maurino (lead artist) 
- A skeleton reminiscent of Omen can be seen on the Jurassic Kog'Maw [ | splash art.
- It was speculated that Omen's thematic space had been filled by Kha'Zix, however Ryan 'Morello' Scott confirmed that they weren't related. 
- A creature resembling Omen can be seen in the Spirit Guard Udyr [ | comic.
- Omen's ultimate was conceived as either an artillery style Bullet Time but in a smaller circle at further range, or as a Cannon Barrage that wasn't global and had to be channeled.