Odin

Donar Vadderung is the head and CEO of Monoc Securities.

Description
During Changes, Donar Vadderung is revealed to be one of the current aliases of the old Norse god Odin, and is a powerful individual easily laying Dresden out with a pure application of his will.

Donar, or Odin, was known to test people on how well they upheld the traditions, obligations and responsibility as guest to host and vice versa. He'd reward the faithful and send a hideous demise to the miserly, callous, or cruel.

Appearance
Donar Vadderung is described as not all that imposing, though a man in good shape in his early fifties, Lean and spare like a long distance runner only with heavy shoulders and arms. His hair was long, a bit shaggy, and the color of a "thundercloud". His one eye was ice blue with a patch over the other eye that bears a vertical scar running from above the eyebrow, through the space where the eye would be, ending at mid-cheek.

Details

 * The top of Monoc Securities where Harry was taken to meet Donar Vadderung is where he said is the center of his power on Midgard. He tells Harry that he could simply wish him dead.
 * Harry describes Vadderung's laugh: "He had a hearty laugh, like Santa Claus must have had when he was a young man and playing football."
 * Uriel said that he knows Vadderung, they are in similar fields. Uriel told Harry to consider Vadderung's words carefully.
 * In White Night, Harry listed the CEO of Monoc Securities as being one of the Freeholding Lords with rights under the Unseelie Accords as a signatory when telling Murphy about what it means. The next day, Harry visited Marcone to be one of the required three members of the Accords to sign for him. "Donar Vadderung" is one of the signatures already on the contract. Marcone said that Vadderung is the current CEO of Monoc Securities. Then in Changes, Gard introduces him "Donar Vadderung, CEO of Monoc Securities".
 * His assistants are called: Hugin and Munin. They don't like Harry much.
 * Harry first met Hugin and Munin when he went to Monoc Securities. They appeared to be pretty, tall, but deadly receptionists.

Changes
In Changes, Harry visits Vadderung at Monoc Securities, led there by Gard at his invitation. Vadderung tells Harry he'll find his daughter in Chichén Itzá in a few days, about the Red Court's plan to use her as a sacrifice in Bloodline Curse. It turns out to be exactly what Harry needed for a successful recovery of his daughter. He also demonstrates his awesome power, which is the same kind of power he'll be facing against the Lords of Outer Night and there will be a dozen of them. Donar further said that Chichén Itzá is the center of their power and that they could just wish him dead that same as he could there at his center.

Near the end of Changes, he makes an appearance at the battle of Chichén Itzá with the Grey Council. He opened a Way for  them—made from green lightning and having a shimmering archway—and again later, those needing to leave. Before he goes, he gives Harry a fencing-like salute with his spear. Ebenezar says that he doesn't give recognition like that lightly.

Cold Days
In Cold Days, Harry meet him at McAnally's Pub to get counsel regarding Demonreach, the dangerous entities imprisoned underneath, their possible release and the island's eminent destruction. He names the destructive fire the Demonreach called the fail-safe that The Original Merlin put in place: "Banefire". He told Harry that should it be triggered, it would mean the end of everything. The also discussed the issue of time dimensions being involved. Harry asked if he can do it, Donar says that he can.

During the closing of Cold Days Kringle (Santa Claus) turns to Harry and winks, briefly showing the visage of Odin. He makes a statement in regard to Mantles and Masks as an explanation.

Quotes

 * "They say you can know a man by his enemies, Dresden. You defy beings that should cow you into silence. You resist forces that are inevitable for no more reason than that you believe they should be resisted. You bow your head to neither demons nor angels, and you put yourself in harm's way to defend those who cannot defend themselves. I think I like you."

Speculation
During Cold Days, Kringle states that he wasn't always known as Santa Claus and that it was a relatively new change, and that he participated in hunts with The Erlking. His position in The Wildhunt is later confirmed, when his hunter's mask was pulled away to reveal Kringle as one of the leaders of The Wildhunt. As mentioned above, during the closing of Cold Days Kringle turns to Harry and winks, briefly showing the visage of Odin. He makes a statement in regard to Mantles and Masks as an explanation.

Throughout Cold Days, the mantles of The Knights, The Ladies and perhaps The Queens as well are all mantles of power that when used slowly erode their host's sense of self, eventually blurring the lines between the bearer of the mantle and the mantle itself, often making the motivations of the bearer of the mantle identical to that of the essence of the mantle itself. That said, much has also been said of the power of free will for those mortals and entities of deep conviction to retain their individual aspects of self. At the close of Cold Days, Mab admits that she was once mortal and could make choices. It could be argued that her inability to act against Maeve was an extension of Mab's separation from the mantle of Queen. Donar Vadderung/Odin/Kringle etc. hints that a mantle and masks have very little functional difference in regard to the heart or motivations of the entity itself, and by his very existence suggests that mantles, masks, and aliases can be assumed, taken up, or discarded based on choice. Who Donar Vadderung really is most likely a mystery. One could argue that the Odin alias might not be the base entity but rather just another mask or mantle. Who or whatever the entity truly is might be described more effectively by their motivations. As such, the being appears to work in mysterious ways, seems to care for mortals enough to get involved, and is an advocate for free will. One thing remains fairly clear, the entity that is known as Donar Vadderung, is adept at taking up, and setting aside mantles of power and may be an example of an entity that uses his mantles as tools rather than the mantle using "Him". This might mean that entities not defined as "mortal" can use elements of free will, or that this entity is in fact mortal. Perhaps the example of Donar Vadderung may serve as an element of hope that those who have to deal with the influence of a mantle of power may retain their free will.