It's a very old, HUGE castle mod with it's very own, unique style. In this video you won't see everything there is to see. Aside from what you see here, the castle also has a court, a dungeon underneath it, secret doors, an alchemy lab, all three, functional guild houses and - despite of what it looks like in the video - a few inhabitants.
The only thing that was never added was a questline or scripts for the NPCs. Which is sad, because this mod is breathtaking.
ATTENTION: I edited the guards, made them female and gave them my armor mash up, the Eagle. In the original mod, they are MALE and wear a recolor of the city guard armor.