Winter Fey

There's an article in Dragon Magazine #374 (April 2009) detailing the Prince of Frost, and some of his winter fey followers. Also known as the Pale Prince, he is the mightiest of the winter fey, but not necessarily their lord - though most of them would follow him if he asked it. He is the son of Tiandra, queen of the summer fey, and used to belong to that court, where he was known as the Sun Prince. When the love of his life ditched him to wed a mortal, his heart turned to ice and he became obsessed with possessing her and destroying the knight. They fled to the Raven Queen, who put their souls in stasis pending a future rebirth and owing her a favor. Ever since, the Prince of Frost has been searching for his reborn love, to make her suffer as much as she made him suffer. His hatred of the mortal realm is his second motivation, desiring to cover it in ice and misery just as it did to him.

Older archfey recall his days as the Sun Prince, and feel pity for him. In kind, the Prince of Frost still holds a certain loyalty to his family and would come to the aid of the summer fey in dire need. Younger, more foolish summer fey actively work against him. The Prince of Hearts from the gloaming fey would be an ally against the Pale Prince, as the Prince of Frost seeks to divide lovers, while the Prince of Hearts seeks to bring them together. The Prince of Heart's assistance would likely come in the form of assisting to reunite the Prince of Frost with his lost love and return him to the days of his joy (and perhaps reverting to his persona as the Sun Prince).

In addition, the Prince of Frost holds an uneasy truce with the Raven Queen - he hates her for what she did to his lover, but respects her power and hold over cold and darkness. In return, she respects his power and honor, along with the other aspects of their domains which are similar. They could be potential allies and consorts.

Although evil, the Prince of Frost is honorable and keeps his word. He respects wit and trickery, and will play games with his foes for the enjoyment of toying with them. Enemies who can play along earn his admiration, though not his mercy.

Regarding other winter fey, from the MOTP:

"The fey lords who choose the path of winter—of deadly cold, biting ice, and blinding snow—are known as the Winter Fey. Although they have no true leader, the most powerful and ruthless of the lot is the Prince of Frost. When he bothers to convene his allies of the long night, his faction is known as the Winter Court. Narrow of build, pale, and light-haired, the Prince of Frost has a smile that does not warm. He is not unnecessarily cruel, but he has not an ounce of mercy in his heart. He allies with other archfey only when facing the direst of threats. The Prince of Frost prefers to deal with his enemies quickly and viciously, with little regard for collateral damage. For some inscrutable reason, the Prince of Frost holds mortals in utter contempt. Although he appears content for now to rule his lands in the Feywild, rumors constantly circulate that he plots to freeze the entire mortal world into one long, eternal glacial age."

Potential plot point - The Prince of Frost and the Raven Queen have formed a truce and an alliance to extend their agendas together. Knowing the other archfey won't support his bid for dominance over the mortal realm, he first needs to neutralize the other factions before he can act (likely throwing them into confusion and disarray, not necessarily destroying them). If the PCs decide to work against him, the info regarding his downfall can be learned from the summer fey (perhaps tricking his mother into revealing info about him), from the RQ herself, or other sources as mentioned in the Dragon #374 article. Allying with the Prince of Hearts could also be beneficial. The Prince of Frost is written as level 31, and if he rises to dominance in the faction war, would prove a worthy epic foe.