Kelvin is an angel who approaches Castiel to offer him redemption.
At some point in the past, Kelvin and Castiel met. Unlike many of his siblings, Kelvin didn't hold a grudge against Castiel for his actions.
Kelvin meets with Castiel and he discusses with his brother the chances of him ever returning to Heaven. Although he admits there are nice things on Earth, he urges Castiel to return, and suggests Castiel should work for his siblings in their bid to assassinate Lucifer's son.
He believes that with Joshua in charge, Castiel can be redeemed. If Castiel works with his siblings in this mission, Kelvin is certain Castiel will be welcomed back home. He then takes Castiel through the portal to meet with the angels.
After Castiel steals the Colt from the Winchesters, Kelvin, joined by Hozai meet with him to use the Colt to kill Dagon and Kelly Kline. After being ambushed by Dagon, Kelvin tells Castiel to kill Kelly and the baby. Dagon kills Hozai and captures Kelvin, but Castiel escapes with Kelly.
At the portal, Dagon kills Joshua and taunts that she had killed Kelvin and been waiting to ambush them for hours.
- Kelvin is the second angel to express surprise at Castiel recognizing them due to only meeting Castiel once. The first was Ephraim in Heaven Can't Wait.
- Kelvin is the fourth angel killed by Dagon, following two unnamed angels and Hozai, and followed by Joshua.
- Kelvin contradicts many standard characteristics for angels. Kelvin is one of the few angels whose name is not of Hebrew origin. He's also one of the only angels who dresses in casual clothing. Although this may have been because he didn't have time to change into formal wear given the situation.