Sam is eventually killed, but is resurrected after Dean sells his soul. ... At the end of the episode, Azazel is finally killed by Dean with the mystical Colt revolver, but not before hundreds of demons are released into the world.

How did Sam and Dean kill Azazel?

In the season 1 finale 1.22 Devil's Trap, when John is being possessed by Azazel, he tells Sam to kill Azazel by shooting him in the heart. In the season 2 finale Dean kills Azazel by shooting him in the heart.

Why did Azazel want Sam?

Being the "most ripe for picking" because he had the "sweetest" heart, Sam was "most desirable for corrupting" of all the children; Lehne described Azazel's thought process as, "If I could turn him, then I had truly won." The character's ultimate motivation, however, is to free Lucifer from his imprisonment in Hell.