Trevor

In life, Trevor was a priest of the Holy Light and friend to Leonid Barthalomew. He died and was risen as an undead during the Third War but was freed from the mindless servitude of the Lich King by Sylvanas Windrunner. In undeath he still wears priestly robes in almost tolerable condition and refuses to wield the shadow even if the Light abandoned him.

One day he discovered a human in the Undercity and recognize him as being the famous paladin, Andarin Lightblade. Leading the chance Trevor proposed him a deal: Trevor wouldn't alarm the guards and Andarin would speak on Trevor's behalf with the Argent Dawn as accepting the priest in their ranks. The deal was made and while the paladin kept the guards at bay the undead freed two prisoners, a mage and a young human girl that Trevor knew well because he called her "my princess".

• Trevor fought during the First War, where he cast "spears of Light", indicating he was a Cleric of Northshire.
• The fact that Trevor called the girl he rescued "my princess" suggests that the imprisoned girl was Calia Menethil, the princess of Lordaeron. This was somewhat confirmed at the BlizzCon 2011 Lore Q&A, when Chris Metzen stated that "There were some hooks in the RPG line that kind of suggested [Calia] was going one way or another."
• Given Alonsus Faol's now-retconned background as the Abbot of Northshire Abbey, it is possible that the story of Trevor inspired the storywriters for the one of Alonsus and Calia in World of Warcraft: Legion.