Grigori

The Grigori were an elite class of powerful angels that were sent to Earth to protect humanity. They were some of the first angels to arrive on Earth, so they most likely kept a watch on humans while they were in the Garden of Eden. They eventually fell from their post, and started to feed on human souls. Most of them were wiped out, but a few of them still remain on earth.

History
The Grigori started out as a squad of elite angels thousands of years ago and were some of the first angels to walk the Earth. According to Tamiel, there were originally hundreds of them and they each had their name engraved on their angel sword. However, they eventually went bad and the other angels hunted them down and killed them. Unknown to the other angels, some of the Grigori survived and began feeding off of human souls as they saw humans as beneath them.

In 2013, a Grigori named Tamiel, after having set himself up as a faith healer named Peter Holloway in Tulsa, Oklahoma for fifty years, begins feeding on the soul of Amelia Novak, the wife of Jimmy Novak, the vessel of his fellow angel Castiel. His actions draw the attention of Castiel and Sam and Dean Winchester when Amelia's daughter Claire begins looking for her. As a result, the Grigori's survival is exposed. While Amelia dies, Tamiel is killed by Claire with his own angel sword.

Characteristics
Being formerly elite angels, the Grigori are shown to be very powerful. One was able to overpower two hunters and a seraph with ease despite their experience in fighting angels. The possess all the standard powers of an angel at presumably a higher level.

They feed on humans by kidnapping people who will not be missed and slowly eating their souls over a period of years. They have been doing this for thousands of years, keeping the victim in the illusion of their own personal heaven while they do this, similar to Djinn. Unlike Djinn however, there is no going back for the victim: other angels can't heal them and they will eventually die of the feeding, even if they are rescued. Due to their habits they are held in disgust by other angels, Castiel outright called them an "Abomination."

Instead of carrying angel blades they carry angel swords that have their names inscribed upon them. They also seem to see the other angels as beneath them as well as humans. Like the Seraphim and Archangels, the Grigori seem to have their powers imbued within them as being cut off from Heaven for thousands of years didn't weaken Tamiel at all and he still displayed healing which is a power regular angels lose when they Fall.

Powers and Abilities
The Grigori are an elite and very powerful class of angel.
 * Immortality - The Grigori have existed for thousands of years.
 * Angelic Possession - Like all angels, the Grigori need a vessel to interact on Earth. Like other angels, they need the vessel's permission.
 * Sedation - A Grigori can put people to sleep with a touch.
 * Perception Altering - A Grigori can put people in dreams of their perfect Heavens and maintain it from a distance except when feeding off of them.
 * Soul Feeding - The Grigori are able to feed on human souls to absorb their heavenly power. The Grigori Tamiel did this by cutting their arms and drawing parts of the soul into their mouths. One indicated that this was inevitably fatal to the victim even if they were rescued and the injuries this caused could not be healed.
 * Healing - As an angel, the Grigori are able to heal injuries and illnesses. Tamiel healed Ronnie Cartwright's blindness.
 * Biokinesis - With just a touch, Tamiel was able to render Ronnie Cartwright blind again.
 * Invulnerability - As angels, the Grigori possess a degree of invulnerability. Tamiel was able to take several bullets to the chest without being harmed at all.
 * Super Strength - Being a higher class of angel possibly equal to or even higher than the Seraphim, the Grigori are unusually strong compared to most angels. Tamiel was able to easily best Sam, Dean and Castiel when they fought him simultaneously.

Weaknesses
Despite them being an elite and powerful group of celestial beings, the Grigori can still be killed by the common methods used to vanquish angels.
 * Angel Banishing Sigil - Like other angels, the Grigori could be banished by the sigil.
 * Holy Fire - Like all angels, the Grigori could be trapped by a ring of holy fire.
 * Angel Blade - Like all angels, the Grigori could be killed by an angel blade.
 * Angel Sword - The Grigori were vulnerable to their own swords.
 * Death's Scythe - Can kill anything in existence.
 * Higher-Tier Angels - While they could overpower a Seraphim, they were presumably vulnerable to the Archangels like all other angels.
 * The First Blade- Grigori are vulnerable to The First Blade like all angels.

Lore
Grigori is slavic transliteration of biblical watcher angels. The word is transliterated from greek, which literally means "fast". The real name of this angel group's in Aramaic, was Iyr(singular) / Iyrin (plural). The apocryphal Books of Enoch (1st and 2nd centuries BC) refer to both good and bad Watchers, with a primary focus on the rebellious ones.

According to the Book of Enoch, the angels of the Lord who were called Watchers descended to earth upon the mount of Hermon after they turned away from heaven. Hermon also means "to swear" as the Watchers "swore" to take wives of human women (this was forbidden by God) due to a strong desire for their beauty. In their lust and subsequent procreation, the Watchers had sons by human women called "The Nephilim" or "fallen ones" (also referred to as the Giants). The Watchers taught their wives and sons forbidden and secret knowledge that corrupted the hearts and minds of mankind which eventually led to the destruction of the first world through the flood of Noah.