Season 4, Episode 16:
On The Head Of A PinSomeone found Lucifer's sword and is using it to kill angels. Castiel and Uriel have captured Alastair and ask Dean to use the torturing skills he learned in Hell to extract information from him so they can stop the murders. Sam is concerned Dean can't handle the job but Dean agrees to do it.Alastair reveals to Dean that because he broke down in Hell and starting torturing, that that was the first seal, and he paved the way for the apocalypse. Castiel feels doubts as he listens to the screams from outside, and Anna - the angel-radio girl who got her grace back - tries to convince him to disobey orders.Sam enlists Ruby to help track down Dean. He drinks some of her blood too, because he needs the strength.Alastair breaks free from The Devil's Trap and starts laying into Dean. Cas comes to his rescue, but Alastair starts sending him back to heaven. Sam arrives and kills Alastair once and for all. Dean is hospitalized after his beating.Uriel confronts Castiel, saying he is the one who has been killing angels, but only the ones who said no. He wants Cas to help him bring Lucifer back and start the apocalypse. Anna kills him before he can kill Cas.
Body countFor this episode = 1 humans, 1 demon, and 2 angels.For the series so far = At least 290 humans (of which 5 were witches), at least 63 demons, 27 ghosts, 10 vampires, 6 changelings, 3 gods, 3 shapeshifters, 3 zombies, 2 angels, 2 werewolves, 1 cat, 1 crocotta, 1 djinn, 1 dog, 1 rakshasa, 1 rawhead, 1 reaper, 1 rougarou, 1 shtriga, 1 siren, and 1 wendigo.