Captain in the Kul Tiras Third Fleet
During the Second War, Derek was in command of a destroyer in the Third Fleet, accompanying his father in battle against the orcish navy. Without warning, they came under attack by dragon riders in the service of the Horde. Though he attempted to warn his father of the danger, Derek was incinerated by one of the dragons as he stood on top of the crow's nest. His boat was sent to the bottom shortly thereafter.
Kurdran Wildhammer and his gryphon riders joined the battle shortly afterward, killing several dragon riders while their gryphons helped slaughter the dragons. The remainging dragon riders fled and were pursued by Kurdran and his brethren, allowing Admiral Proudmoore to focus on destroying the orcish navy, ensuring his son's death wasn't in vain.
- In the RPG, Derek has another brother, Tandred Proudmoore, but Blizzard has stated he will not be made canon.