Lilith

Background
Lilith is a demon who is an "up-and-coming" player in the war. Her eyes are white, unlike most demons. She is from the west and is after Sam Winchester. The body she mainly possesses is that of a little girl, but will sometime use an older, prettier woman to seduce the boys. Sam and Dean will be hunted and hunting her in the coming episodes.

In the episode "Time Is on My Side", it is revealed that Lilith is the demon that holds Dean Winchester's one-year-to-live contract.

In the episode "No Rest for the Wicked", Lilith attempts to kill Sam but fails, proving his immunity to her powers. It has not yet been revealed as to why this is, but Sam is definitely her 'competition' as Ruby mentioned.

in Season 4 Episode 2 "Are you there God it's me Dean Winchester" The Angel Castiel Reveals to Dean That Lilith is attempting to break the 66 Seals that will release Lucifer.

In "The Monster at the End of This Book". Lilith mentions to Sam that she will not survive the war and wishes to reconcile with the Winchesters if they self-sacrifice themselves.

Appearances

 * "Jus In Bello"
 * "No Rest for the Wicked"
 * "Yellow Fever"
 * "The Monster at the End of This Book"
 * "The Rapture'"