Is it possible to Soul Trap Lord Harkon? I know he's a vampire, and undead and I thought you weren't supposed to be able to Soul Trap them, but I always seem to have filled soul gems when I leave a Nordic Tomb, but I want to know if I can Soul Trap him and, if so, do I need a Black soul gem or the Black Star or will a Grand one do?

I try to capture specific souls and use them for specific enchantments. Ulfric's so I can fortify my chest piece's armor so I can defend Skyrim as he would want me to. Titus Mede II's on my weapons to bring the fight to the Elves etc. I want to use Harkon's to make some Magicka enhancing amulet for Serena since, you know, she really wants to be a family again, but that can't happen, but here comes the sensitive Dragonborn giving her a piece of him to keep close to her heart... cue the sappy music.

So yeah, can Harkon be soul trapped or not?