Archangel (spirit being)

Archangels are powerful beings who serve God. Directly translated from Greek, "archangel" means "first" or "ruling angel" (the term angel comes from "angellos" meaning "Messenger").

Powers
Archangels are high ranking angels who possess unfathomable power that exceeds that of any other character directly encountered in the series. In Skin Game, when Harry Dresden suggests that Uriel would be capable of destroying the solar system, he corrects him by stating that he had the power to obliterate several galaxies. Nevertheless, a set of extremely restrictive "rules" or even "laws" appear to limit the extent to which archangels can exercise their power, although some can apparently be bent, particularly by Fallen Angels, such as when a Fallen influenced Dresden in Changes or when a powerful entity worked with the Denarians in Small Favor to create the massive pentacle. When the rules are violated in such manner, agents of God are allowed to balance the scale, though not to retaliate.

In Skin Game, Uriel reveals that archangels like him have the power of transubstantiation : an archangel can pass his Grace to a mortal, temporarily giving them all of his power—and obligations. Should the mortal choose to use that power for evil or break the rules restricting the archangel's act, the archangel who entrusted them his Grace will Fall. Furthermore, until the mortal returns the Grace to him, the archangel himself becomes mortal and vulnerable just as humans are.

Uriel
Uriel, also known as the Watchman, is the archangel with the most extensive interaction with Harry Dresden, acting as a guide, mentor and advisor.

Amitiel
Amitiel stood guard at the Office in Between, appearing for what he is when Harry Dresden used his Sight; his gun morphed into a glowing sword that glowed, and his named appeared on his name tag. He gently stopped Dresden, blocking his Sight. He apologized stating that Harry Dresden might have been harmed.

Michael
Michael, also known as Prince of the Host, is the archangel who offered Esperacchius to Sanya, after the latter left his Fallen, Magog, in Venice.

Other archangels
In Small Favor, Queen Mab identifies four Archangels without calling them by name: the Prince of the Host, the Trumpeter, the Demon Binder, and Watchman.

In Skin Game, Harry Dresden muses about the consequences of an archangel Falling.

Fool Moon
In Fool Moon, Harry believes the third circle of Harley MacFinn's greater circle of power could hold archangels.

Ghost Story
In Ghost Story, Uriel shows Harry that a dark angel had been whispering lies into his ear that robbed him of his free choice and brought him to believe that he could only end his life.

Fan speculation
It has been speculated that Anduriel was the Fallen who tricked Harry Dresden out of free will in Changes (brought to light in Ghost Story); however, there is an alternate theory that Dresden was lied to by Lucifer. Based on the speculation that the term "Fallen" refers to any Fallen Angel and not necessarily one of the Order of the Blackened Denarius and the details put forth in the conversation between Harry and Uriel at the close of Ghost Story in regard to balance between the influence of the Archangels and that of the Fallen makes it conceivable to think that the fallen who lied to Harry was of an order equal to Uriel (whereas the Denarian have consistently been countered by the Knights of the Cross and not directly by Uriel). As above, Uriel's implication of a fifth archangel who has fallen would leave only one option. Further speculation in regard to the medium of inference with Harry’s free will (lies), may also add credibility to this theory as Lucifer is also known as the "Father of Lies". This speculation also seems to fit the past aspects of Uriel's balanced influence in opposition to the Fallen during the events in Small Favor.