A drow warlock
Trax is a drow from the Underdark city of Lelthaz’ran. During his life, he would disguise himself as various nobles and work his way into the different houses of the city. When he wasn’t doing that, he was a member of a scouting party. One one particular scout, he swore he saw a surface elf in the tunnels. He silently followed in hopes to kill it and bring it back to the city. This strange blue-colored elf led him far enough away that he actually got lost and ended up following it onto the surface world. The elf had disappeared but had left behind a strange coating of ice and a dead body with a backpack full of strange items.
The strangest was a crystal that looked like a piece of ice and felt cold. But it never melted. Trax began experiencing strange feelings and abilities manifested over the next few weeks. He saw visions of an ice palace and the blue elf smiling. Somehow, this being was connected to these strange powers. Trax would have to find out.