|Dates||Before humanity - 2011 (killed by Castiel)|
|Episode(s)|| 6.03 The Third Man|
6.11 Appointment in Samarra
6.15 The French Mistake
6.17 My Heart Will Go On
6.21 Let It Bleed
6.22 The Man Who Knew Too Much
The footsteps I'm following, they're yours. What you did, stopping the big plan, the prize fight? You did more than rebel. You tore up the whole script and burned the pages for all of us. It's a new era. No rules, no destiny. Just utter and complete freedom.
– Balthazar, 6.03 The Third Man
Balthazar is an angel of Heaven who fought alongside Castiel and Uriel. Castiel thought that he had died in battle. In fact, Balthazar faked his death to hide his departure from Heaven, and took a number of powerful artifacts, including the Staff of Moses and Lot's Salt, with him. He has been on Earth enjoying a rather hedonistic lifestyle.
Balthazar's powers and abilities are similar to those of other angels.
Balthazar is able to influence the movement of objects and people using his mind. He can also teleport himself and others through time and space. Like all other angels, he is able to manipulate time. He can also overpower humans and demons.
While investigating cops who have died of plague like symptoms, Sam, Dean, and Castiel find that Aaron Birch, the young brother of a man the cops murdered, has a piece of the Staff of Moses, which Balthazar sold him in exchange for his soul. Castiel finds out it was Balthazar through reading a mark on the boy's soul. He then does an Enochian ritual to find Balthazar.
Balthazar tells Castiel that he has no intention of returning to Heaven, and he flees when Raphael appears with other angels outside the house. Sam and Dean banish two angels outside with an angel banishing sigil and Castiel kills one inside with his angel sword, but Castiel is then confronted by Raphael and overpowered. Balthazar reappears and destroys Raphael's Vessel with Lot's Salt, which turns him into a pillar of salt. Sam and Dean then trap Balthazar in a ring of holy fire and force him to give up Aaron's soul. They want to get more from him, but Castiel releases him because he owes him his life.
Sam uses an Enochian ritual to summon Balthazar to him. When Balthazar appears up in a loft, he teasingly asks why he hasn't summoned "his boyfriend" - Castiel. Sam asks him if there is any way to keep a soul out of its body. Balthazar informs him of a ritual that involves Sam defiling his body; his reason for helping Sam is that he would find it useful to have Sam in his debt. He tells Sam that he would need the blood of his father (that needn't come from the "father of your blood") to keep his soul out of his body.
Balthazar suddenly appears at Bobby's house and tells Sam and Dean that Raphael intends to kill everyone who ever helped Castiel. He does not explain the situation, but quickly starts gathering Dead Sea brine, lamb's blood, and the bones of a lesser saint, which then he uses to draw a sigil on a window. He gives a key to Sam to guard and then Virgil, Raphael's angel assassin, arrives, so Balthazar quickly tosses Sam and Dean through the window, sending them to a different universe.
Later it turns out that sending the Winchesters into a different world with a bogus key was part of Balthazar and Castiel's plan to divert Raphael's attention from what they were really doing. While Virgil and Raphael were focused on Sam and Dean, Balthazar was able to gather the stolen weapons of Heaven and give them all to Castiel. When Raphael arrives to kill Balthazar, Sam, and Dean, Castiel appears and threatens Raphael with the weapons now in his possession, forcing him to leave.
While trying to determine why descendants of people who sailed on the Titanic are being killed, Sam and Dean find a picture of the ship's crew, and see Balthazar posing as First Mate I.P. Freely. They summon him, and he admits to going back in time and saving the previously doomed ship. He claims that he did it because he hated the movie and Celine Dion's theme song. Balthazar also reveals that the timeline has changed so that Ellen and Jo are alive and Dean drives a Ford Mustang.
The brothers discover that Fate has orchestrated the killings, and after Castiel narrowly saves them from her, they attempt to kill her. When she next attacks Sam and Dean, time freezes and Castiel confronts her. She accuses him of ordering Balthazar to "unsink" the ship, and insists that he follows Castiel's orders. While they are speaking, Balthazar sneaks up behind Fate with a gold dagger. Castiel stops him at the last instant, and agrees that they will go back and sink the ship to save Sam and Dean from Fate.
Planning to get back Lisa and Ben Braeden from Crowley who has taken them hostage, as insurance that Dean and Sam will not interfere, the Winchesters, because they no longer trust Castiel, summon Balthazar. He seems unaware of Castiel's collaboration with Crowley, and refuses to help them.
After learning about Castiel's plans and motives to crack open a door to Purgatory, Balthazar confronts the angel in a forest and they talk. Castiel affirms his plan to Balthazar, admitting that he intends to absorb the souls of Purgatory inside his vessel, which could imbue him with the power to defeat Raphael. Heavily concerned, Balthazar reminds him that if he were to fail, the process could devastate not only him, but the world as well. Still, when Castiel asks him for his loyalty, Balthazar gives it.
Back at Bobby's house, Balthazar appears and tells Sam and Dean that he's decided to be their double agent because Castiel is out of control. He's found Lisa and Ben, but can't get close because Crowley has angel-proofed the building they're in with Enochian sigils. They seem reluctant to trust Balthazar, but he takes them to where Lisa and Ben are being held and then leaves.
As Dean and Bobby watch over Sam, who has been unconscious since Castiel dissolved the wall in his mind that was preventing him remembering Hell, and his year of being soulless. Balthazar arrives and betrays Castiel by giving up Crowley's hiding place.
Castiel confronts Balthazar. He says that Dean is coming, and someone among them is a traitor. Balthazar asks him who it is, and Castiel tells him that he doesn't know, but he wants Balthazar to investigate. While the other angel is distracted, Castiel teleports behind him and stabs him through the back with an angel sword, killing him.