Supernatural

Angels

The angels on Supernatural aren't like the angels you're used to. Introduced to the show's lore in season 4, they're fierce warriors and proficient fighters, sworn to follow the Word of God. After Sam and Dean stopped the Apocalypse and trapped Michael and Lucifer in the Cage, Heaven fell into a civil war, leaving many of the angels casualties to the violence, and now there are only a handful of angels left from the thousands God created.

Demons

Demons are formed from the tortured souls of humans who were sent to Hell. They are treacherous, conniving, and will manipulate you any which way to get what they want. There is a hierarchy in the kingdom of Hell, ranging from low level demons to knights and princes of Hell to the King of Hell himself (though this position is currently filled by the witch Rowena.) Some demons have become allies of the Winchesters, but they are few and far between, and usually end up dead (again).

Ghosts

Ghosts have been synonymous with Supernatural since the beginning of the show. Many ghosts become vengeful spirits because they feel they have unfinished business in the mortal world. A potential haunting is characterized by cold spots and flickering lights, among other possible signs. The tried and true way to get rid of a vengeful spirit is to salt and burn the ghost's bones.

Leviathans

The Leviathans of Purgatory were the main villains of season 7 on Supernatural. Leviathans are creatures with a taste for humans. Led by Dick Roman, they planned to systemtically slaughter humans to satisfy their appetites. Leviathans' weakness is Borax or Sodium Borate, found in cleaning prodcuts, and they can be temporarily killed by decapitation.

Vampires

The lore surrounding Supernatural's vampires is much different than our own folklore. According to John Winchester, "a cross won't repel them, sunlight won't kill them, and neither will a stake to the heart." The only way to kill a vampire on the show is by beheading them, though they can be incapacitated by dead man's blood.

Werewolves

Werewolves are normal humans until the full moon, the only time they turn. They have yellow eyes, fangs, claws, and enhanced senses. Silver is the proven way to kill a werewolf, usually in the form of a silver bullet to the heart. While most werewolves are dangerous, some werewolves, like the Winchester's friend Garth Fitzgerald IV and his wife Bess, do not attack humans and instead live off of cow hearts.