Nephilim

"A Nephilim, an abomination. She's the offspring of an angel and a human."

- Metatron to Castiel Nephilim is a hybrid creature born from the union of an angel and a human. Castiel stated that creating a Nephilim is forbidden; however, Metatron revealed in "Clip Show" that there was one existing on Earth. Metatron viewed this Nephilim as an abomination due to her existence being outlawed.

Characteristics
As stated, Nephilim are the result of sexual reproduction between a human and an occupied angel vessel, the latter giving the offspring angelic properties. Nephilim are only created if their angelic parent has his or her grace during conception, which seems to be the source of what makes a Nephilim. If an angel mates with a human without its grace, the resulting offspring will be completely human. Nephilim have glowing eyes like an angel, although their glow is somewhat dim and grayish in color as opposed to the bright white or bluish-white glow of regular angels.

Known Nephilims

 * Jane
 * Justin doyle

Powers & Abilities

 * Astral Perception - A Nephilim can perceive the true form of angels without harm.
 * Super Strength - Their angelic ancestry endows Nephilim with enhanced strength sufficient to overpower and even toss common angels around. One was able to throw around a wounded seraph.

Weaknesses

 * Angel Blade - Being technically half-angel, Nephilim can be killed by an angel blade.
 * Death's Scythe - Can kill anything.
 * The Colt - The Colt can kill almost anything in existence.