He was an alternate universe version of Lucifer.
Lucifer was described as having been "torn apart" in the skies over Abilene by Michael. His death led to Michael becoming the victor of their world.
When Michael discovered another Lucifer who had crossed over from another reality, he informed Lucifer of his counterpart's fate and intended to treat this Lucifer the same way. He easily overpowered him in combat.
- This Lucifer shares the opposite fate of the Lucifer from the 2014 apocalyptic reality, in which Lucifer in that reality is the victor.
- This is the only known version of Lucifer to have died.
- Since Sam Winchester never existed in his world, it's unknown who this Lucifer's true vessel was.