Metatron

Metatron is the archangel whom according to Castiel, wrote down the Word of God when creation was being formed. The Word of God was inscribed on multiple stone tablets in a ancient language that almost all beings, including angels, can not read. One of these tablets containing the Word had instructions on how to kill the Leviathans should they escape from Purgatory and one tells of how to lock the Demons in Hell forever. Metatron was later mentioned by Kevin Tran when reading the Word of God to Crowley.

While Kevin was reading the tablet on demons, the prophet saw a personal note by Metatron. It mentions the archangel taking leave of his master and letting humans take responsibility of the compendium of tablets.

His current status and location is unknown, largely because of his departure from Heaven. Why he did this is unclear. It is also not yet mentioned how he is related to the other four archangels

Power and Abilities
Being an archangel Metraton is certainly a very powerful, with various powers of an angel if not all, however distinguished above all by their knowledge.
 * Cosmic Awareness - As the scride God, wrote several words of God about various beings, having thus has a huge knowledge of many creatures including Demons, Leviathans and Angels.
 * Teleportation - He traveled from Heaven to Earth, to relinquish the tablets.