Angels

Angels are extremely powerful beings that were created by God. They were created before humans. But although both were created by God, angels are very different from humans.

Characterization
Angels are so powerful that other beings can't look upon, with their actual eyes or psychically, their true forms without consequences. If a human or even a demon sees an angel's true form they're eyes will actually burn until they're completely gone causing blindness. This happened to Pamela Barnes when she used her psychic powers to see the true form of Castiel. Although no angel's true form has actually been shown it can be implied that angels do actually have wings. In "Lazarus Rising", Castiel displays his two wings through his shadow. Also, in "Dark Side of the Moon", Zachariah tells Dean and Sam that in his true form he has six wings and four faces, one of them being that of a lion's. It's possible that the number of wings an angel possesses represents their rank or power since Castiel was shown to have two wings, while Zachariah, his superior, says that he has six.

Anna Milton describes angels as being emotionless unable to have feelings such as, loyalty, love, and forgiveness. She even goes on to compare angels to statues in the sense that they're both cold and have no choice. Unlike humans, angels do not reproduce. Anna tells Dean Winchester that one of the things that humans have that angels don't is sex. Dean even describes angels as "Ken dolls" meaning that the only way for them to have sex is to possess a human.

Powers

 * Teleportation (displayed by all angels)
 * Telekinesis
 * Possession (displayed by all angels)
 * Enhanced Strength (displayed by all angels)
 * Exorcism 
 * Enhanced Endurance (displayed by all angels)
 * Voice Mimicry (displayed by Castiel)
 * Healing 
 * Resurrection (displayed by Castiel & Michael)
 * Time Manipulation (displayed by Michael, Castiel, Anna, & Zachariah)
 * Reality Warping (displayed by Gabriel & Zachariah)
 * Telepathy (displayed by Anna & Castiel)
 * Memory Manipulation (displayed by Michael)
 * Pyrokinesis  (displayed by Michael only)

Weaknesses
Angels are very hard to kill. The methods that are used to hurt or kill demons will not affect them at all. In On the Head of a Pin, Uriel states that the only thing that can an angel is another angel. Although there are not many known, there are methods to stop or kill an angel:
 * Blood Seal
 * Exorcism Chant
 * Holy Oil
 * Colt - Castiel believed that the Colt was the only thing that could possibly kill Lucifer. Although, a shot to the head failed to kill Lucifer, it can still be implied that the Colt is capable of killing weaker angels, such as Castiel

Known Angels

 * Castiel
 * Anna Milton
 * Uriel
 * Joshua
 * Lucifer (archangel)
 * Michael (archangel)
 * Gabriel (archangel)
 * Raphael (archangel)
 * Zachariah