Killed by Castiel

Beings killed by Castiel.

Archangels

 * Raphael - Exploded at the molecular level while empowered by the souls of Purgatory.

Intelligence Angels

 * Ion - Pushed an angel-killing bullet through his eye to escape Ion and Crowley.

Reapers

 * Billie - Stabbed through the back with an angel blade to break her deal with the Winchesters.

Regular Angels

 * One of Raphael's Incursion Angels - Stabbed with an angel blade during the Skirmish at Balthazar's Mansion.
 * Pharmacist Angel - Stabbed with an angel blade in self-defense.
 * Balthazar - Stabbed through the back with an angel blade after discovering Balthazar had betrayed him to the Winchesters.
 * Bartholomew - Stabbed in the abdomen with an angel blade in self-defense.
 * Daniel - Stabbed through the back with an angel blade to save Hannah.
 * Efram - Stabbed in the chest with an angel blade.
 * Adam's Angel Escorts - Stabbed with an angel blade at Adam Milligan's resurrection site.
 * Three of Malachi's Faction - Stabbed with an angel blade after stealing Theo's grace.
 * Hael - Stabbed in the chest with an angel blade after being pressured to become her vessel.
 * Ishim - Stabbed through the back with an angel blade to save Lily Sunder.
 * Raphael's Loyalists - Smote in Heaven after declaring himself "the new God."
 * Jonah - Stabbed in the abdomen with an angel blade.
 * Rachel - Stabbed with an angel blade in self-defense.
 * Samandriel - Stabbed in the stomach with an angel blade while under the control of Naomi.
 * Theo - Throat slit and grace absorbed then smote.
 * Zachariah's Foot-Soldiers - Stabbed through the neck and the back respectively with an angel blade in order to save Sam and Dean Winchester.
 * One of Zachariah's Guards - Stabbed with an angel blade outside the Green Room.

Rit Zien

 * Ephraim - Stabbed in the chest with an angel blade.

Nephilim

 * Jane - Stabbed through the neck with an angel blade and cut out her heart for Metatron's spell.

Princes of Hell

 * Dagon - Incinerated while empowered by Jack.

Regular Demons

 * Crowley's Assassins - Smote to protect the Winchesters and Bobby Singer from an attack.
 * Pestilence's assistant - Stabbed in the abdomen with the demon-killing knife after defeating Pestilence.
 * One of Dean's Captives - Smote to save Dean's life.
 * Ellsworth - Forced back into his vessel and then smote so that he could not tell the Winchesters that Crowley is alive.
 * An unnamed demon - Tortured for information on the location of Cain then stabbed through the chest with an angel blade.
 * One Iowa Factory Guard - Smote while rescuing Kevin Tran and the future Prophets.
 * Ellsworth's Hunters - Two demons capturing monsters for Elsworth who were smote by Castiel to keep the Winchesters from finding out the truth about Crowley's survival.
 * Marcus - Smote by Castiel at the Northern Indiana State Hospital to save Sam Winchester.
 * Demon Medics - Smote by a memory-less Castiel outside the Northern Indiana State Hospital.
 * Demon Ann Morton - Smote during the Hunt for the Angel Tablet.
 * Demon Wendy Rice - Stabbed with an angel blade on the orders of Naomi to keep the demon from telling the Winchesters about the angel tablet.
 * Hundreds of demons - As an angel, Castiel has killed hundreds of demons over the millennia.

Jefferson Starships

 * Around a dozen Jefferson Starships - Blasted with holy white light.

Leviathans

 * Dick Roman - Briefly restrained so Dean could stab Dick through the neck with the Bone of Righteous Mortal Washed in the Three Bloods of Fallen.

Vampires

 * Lenore - Smote at her request.

Zombies

 * An unnamed Croatoan zombie - Decapitated with a shotgun blast to save Sam's life during the Raid on Niveus Pharmaceuticals.

Other Monsters

 * Crowley's Monster Prison - Killed all of the monsters within the prison at the Winchesters' request.
 * Brigitta - A djinn held prisoner by Crowley when Castiel slaughtered the prison's inhabitants.
 * Unnamed Rugaru - One of the prisoners.
 * Unnamed Purgatory monster - Smote while fighting alongside Dean and Benny Lafitte.

Vessels

 * Alfie - Killed along with Samandriel by Castiel.
 * Gloria Lewellen Jacobson - Killed along with Hael by Castiel.
 * Ann Morton - Killed along with the demon possessing her by Castiel.
 * Wendy Rice - Killed along with the demon possessing her by Castiel.
 * Balthazar's vessel - Killed along with Balthazar by Castiel.
 * Bartholomew's vessel - Killed along with Bartholomew by Castiel.
 * Ephraim's vessel - Killed along with Ephraim by Castiel.
 * Ishim's vessel - Killed along with Ishim by Castiel.
 * Raphael's second vessel - Killed along with Raphael by Castiel.
 * Numerous other vessels - Killed along with the angels possessing them by Castiel.

Four Horsemen of the Apocalypse

 * Pestilence - Cut off his ring with the demon-killing knife, leaving him permanently incapacitated.