Nick

Nick was a solemn and lugubrious widower who lived in Delaware who became the primary vessel of Lucifer until he possessed Sam Winchester instead. Several years later, Nick's body was restored and improved by Crowley to act as Lucifer's vessel once more.

Early Life
Nick was married to a woman named Sarah, and together they had a child. One night, a criminal crept into their house and murdered Sarah and the baby in their beds. After the home invasion, Nick still resided in the house, and kept some objects that were connected to Sarah and the baby.

Season 5
In Sympathy for the Devil, Nick started hallucinating Sarah and his baby, and their blood. Lucifer appeared as his wife Sarah and told him that he was a vessel, and that Lucifer wanted his consent to possess him. Nick, believing it was a dream yet doubting it was, nonchalantly refused. Lucifer told him that he was misunderstood, that he was punished for "loving God too much". He promised Nick justice for his family. Nick consented to possession.

In Abandon All Hope..., Nick's body began to develop burn-like sores from containing Lucifer's essence. When Castiel mentioned the sores appearing on his vessel's face, Lucifer admitted that Nick was "wearing a bit thin."

In Hammer of the Gods, Nick's body had deteriorated further under the effort of containing Lucifer and massacring the Pagan Deities.

In Two Minutes to Midnight, Castiel told Sam and Bobby Singer that Lucifer would have to have been drinking gallons of demon blood in order to help maintain the integrity of Nick's body.

In Swan Song, Dean and Sam met up with Lucifer at an abandoned apartment in Detroit. Nick's body had degraded even further from the immensity of Lucifer's essence. Sam agreed to be Lucifer's vessel, and Lucifer then left Nick and entered Sam, leaving Nick dead on the floor next to the dead vessels of Lucifer's Guards.

Season 7
In Meet the New Boss, Sam starts hallucinating and sees Lucifer, in the guise of his vessel Nick, without the burn marks. The hallucination retains the form of Nick throughout its appearances.

Season 11
In O Brother, Where Art Thou?, Lucifer manifests inside a cage in Limbo in the form of Nick despite having no vessel.

In Hell's Angel, Lucifer takes on Nick's form again when confronting Crowley inside Castiel's head.

In We Happy Few, while Amara extracts Lucifer from Castiel, Lucifer takes on the form of a transparent Nick overlapping Jimmy's body.

Season 12
In Stuck in the Middle (With You), while trapped within a small cage in Crowley's throne room, Lucifer manifests in the form of Nick.

In Family Feud, Crowley reveals to Lucifer that his demons found Nick's body a few years before and repaired and improved it so it would be "a fitting final home" for Lucifer. When Rowena MacLeod had cast Lucifer back into the Cage, Crowley perverted the spell so instead Lucifer was sent into Nick's body. Lucifer thanks Crowley, but wonders how Crowley really expects it to end.

In Somewhere Between Heaven and Hell, Lucifer briefly escapes his chains only to have Crowley reveal that Nick is his true prison, Crowley having warded Nick's body based on Lucifer's Cage to restrain him while the chains were just ornamental.

In The British Invasion, Drexel examines Nick's body for Lucifer and tells him that the repairs to Nick's body are complete and he is a sound vessel for Lucifer. However, Drexel is unable to remove Crowley's "security system." On Lucifer's command, he promises to try.

In There's Something About Mary, Drexel continues his work on removing Crowley's security system from Nick's body. While he is unable to remove it, Drexel's efforts cause it to power up in reverse, giving Lucifer control over Crowley's vessel. With this, Lucifer is able to make Crowley's vessel unconsciously mimic his own movements in Nick. After apparently killing Crowley, Lucifer is free upon the Earth once more with Nick as his permanent vessel. Once Lucifer has his freedom, he changes Nick's wardrobe slightly, now donning a black leather jacket rather than his usual outfit in Nick's form.

In Who We Are, moments before being killed by Jody Mills, Doctor Hess presents Sam with a picture of Lucifer in Nick's body outside of Crowley's lair and informs him of Lucifer's escape.

In All Along the Watchtower, Sam shows Dean and Mary the picture of Lucifer outside Crowley's lair. Sam notes that its definitely Lucifer as he recognizes Nick as Lucifer's vessel. While confused as to how its possible, Sam correctly surmises that Crowley is responsible.

Physical Appearance
Nick has messy, short blond hair and light blue eyes. He is six feet and one inch tall, making him shorter than Lucifer's true vessel, Sam Winchester, by three inches.

His usual attire consists of a green T-shirt, a dark green shirt hanging loose, blue jeans and dark shoes. Although he was wearing a white shirt and sweatpants when he assented to possession, Lucifer changed into this attire and continued to use Nick's guise when not occupying a vessel.

Nick's wedding ring is also worn by Lucifer.

After breaking free of Crowley's control, Lucifer dons a brown leather jacket over a white shirt.

Season 5

 * Sympathy for the Devil
 * Free to Be You and Me
 * Abandon All Hope...
 * Hammer of the Gods
 * Swan Song

Season 7

 * Meet The New Boss
 * Hello, Cruel World
 * Repo Man
 * The Born-Again Identity

Season 11

 * O Brother, Where Art Thou?
 * The Devil in the Details
 * Hell's Angel

Season 12

 * Stuck in the Middle (With You)
 * Family Feud
 * Somewhere Between Heaven and Hell
 * The British Invasion
 * The Future
 * There's Something About Mary
 * Who We Are
 * All Along the Watchtower

Season 13

 * Lost & Found
 * The Rising Son
 * War of the Worlds
 * Various & Sundry Villains
 * Devil's Bargain
 * Only the Best Intentions

Trivia
Nick
 * The name 'Nick' is possibly a reference to 'Old Nick', which is a nickname for the Devil.
 * When Lucifer is yanked from Castiel by the Darkness, his true form appears as Nick for a moment before he disappears.
 * Nick is the second vessel whose body is restored specifically for an angel to possess as his vessel. The other vessel is Jimmy Novak whose body was restored by God for Castiel's use.
 * The method Lucifer uses to approach Nick is later used on Vince Vincente. Both are subjected to blood that horrifies them, and meet with Lucifer who takes on the guise of their deceased lover or wife.
 * Given the alternate reality version of Michael's inability to recognize the main reality Lucifer along with several other angels, Nick was presumably not the vessel of the deceased alternate reality Lucifer. It is unknown who he used as Sam never existed in that world.