Criston Cole (Dancing Dragons)

Ser Criston Cole is the Lord Commander of the Kingsguard. When he was first knighted, he was the sworn sword of Princess Rhaenyra Targaryen. For years, he was her closest companion and dearest friend. However, the night before her wedding to Laenor Velaryon, he confessed his love for her and asked to run away together. Though Rhaenyra cared for him, she was not in love and she was unwilling to forsake her claim to the Iron Throne. This dismissal infuriated Criston and he instead left her service in favor of Queen Alicent Hightower. Since Rhaenyra wants the Iron Throne, he has worked for years since her marriage to ensure that she never gets it. To that end, he allowed Viserys I Targaryen to be poisoned by Alicent and a coup to be staged to ensure Rhaenyra was denied her birthright.