Vessel
A Vessel is a human that an angel possesses in order to manifest on Earth.
The suitability to be a Vessel is innate. Castiel makes reference when possessing Claire Novak that her suitability as a vessel is "in her blood". Castiel can speak with Jimmy Novak from the Heaven's without using a mouth piece, this was proven in 4.20 The Rapture.
Michael, when he is using the young John Winchester as his vessel, tells Dean: “You’re my true Vessel, but not my only one”. It’s a bloodline…stretching back to Cain and Abel. It’s in your blood, your father’s blood, your families blood.”
While Demons can possess any human against their will in order to manifest, Angels must contain the consent of the human before they can enter them. However, as Zachariah's treatment of Dean in attempts to get him to agree to be Michael's vessel demonstrates, this consent can be coerced.
Vessels
True Vessels
Many Angels such as Gabriel have told Dean and Sam that they were destined to be the vessels for the two Archangel's. Zachariah told Dean on many occasions that he is special and that he was chosen to be the vessel for Michael.
- Dean - the chosen to be the vessel for Michael, but is adamant he will not consent. Micahel tells him if he consents, he will not be that he will not be left "a drooling mess" afterwards.
- Future!Dean tried to consent to be a Vessel but it was too late as the entire Host of Heaven gave up on stopping Lucifer after the release of the Croatoan Virus
- Sam - chosen to be the vessel for Lucifer. Sam is revealed to be Lucifer's true vessel. It is mentioned twice that “Sam consent to be Lucifer’s vessel during a confrontation in Detroit. 5.04 The End5.10 Abandon All Hope
- Jimmy Novak is the vessel for Castiel. While he initially consented, when Castiel was taken back to Heaven, he is keen to resume his life with his family. He said that being possessed was like being "tied to a Comet".
Raphael destroyed this Vessel when he kills Castiel 4.22 Lucifer Rising but when some power brings Castiel back, this vessel is intact.
- Claire Novak is Jimmy's daughter and is briefly a Vessel for Castiel. After Jimmy was shot by a demon possessing his wife, Castiel possesses his daughter Claire Novak. Jimmy (near death) begs to be allowed to be his vessel again. It is not stated what happens to Jimmy Novak.
- Donnie Finnerman is the vessel for Raphael. Castiel says there is a connection between a vessel and an Angel, and that he can summon Raphael back to the vessel. He uses the Enochian Water Cup Ritual to do this. After his encounter with The Archangel named Raphael, he was left in a Catatonic state.
- Gabriel - it is unknown who his vessel is.
- Zachariah - it is unknown who his vessel is. While talking to Dean Zachariah made a comment in which he said that humans are filthy and disgusting (smelly things).
Plan (B) Vessels
Plan "B" vessels are vessels that were chosen at the last moment; Lucifer and Azazel planned for Sam to be Lucifer's true vessel. Plan "B" vessels tend to suffer. Nick is currently rotting away and his flesh is pealing. If Lucifer's spirit possesses a normal human (Nick) eventually the person’s body will start to wither away and their skin will rot and their flesh will peal, Nick is going through this process. Lucifer even stated that Nick was “wearing a bit thin.” 5.10 Abandon All Hope
It currently remains unclear what happens to the plan "B" after this process, however Lucifer did say that Nick is close to spontaneously combusting, for Nick apparently can not contain Lucifer for long periods of time.
- Nick- Nick is a man who was grieving for his murdered wife and child who consents to be Lucifer's Vessel when Lucifer promises to help him get justice for his family. Lucifer later tells Sam that Nick is not the ideal vessel and can barely contain him.
- Young John Winchester- Michael used young John Winchester as his temporary vessel. As Michael said it runs in the Winchester blood-line, this enabled him to use John as a "Plan B" vessel.
Other uses of humans by Angels
Lucifer used a dead nun as a mouth piece to communicate with Azazel at St. Mary's Convent. Prophets , like Chuck , are also a method through which Heaven communicates with humanity, but they are not physically possessed by angels.
