Possibly the most annoying NPC in the game.

is that the guy from the Thalmor Embassy?

No, it's the guy at Kolbjorn Barrow in Solstheim. Apparently, a potential follower if you spare him. Why would you though? He demands 11K from you to hire people to dig up the barrow, then sacrifices all of them to his master (i.e. kills them) and pretends that he doesn't remember, until you tell him that he needs to be punished. Then says "I have his will on my side! He will command all of us!" and attacks you.

In this screenshot, he looks like he's trying to use the spell which he used to wake up his master, to wake up something else. It is time! Arise!

1 hour ago, bjornk said:

No, it's the guy at Kolbjorn Barrow in Solstheim. Apparently, a potential follower if you spare him. Why would you though? He demands 11K from you to hire people to dig up the barrow, then sacrifices all of them to his master (i.e. kills them) and pretends that he doesn't remember, until you tell him that he needs to be punished. Then says "I have his will on my side! He will command all of us!" and attacks you.

Oh, right... the other one is a wood elf... I think same haircut.

1 hour ago, bjornk said:

In this screenshot, he looks like he's trying to use the spell which he used to wake up his master, to wake up something else. It is time! Arise!

It's been a very long time since I've been able to replay Dragonborn DLC because when I used to complete the main quest and then move on to finish Dawnguard, my save was so bloated it would cause instabilities. And Solstheim has always been a place where it loves to crash when traveling in the ash part of the area.