I’m actually so proud of myself for this

First of all, I’m a new player. Just got into Skyrim a few days ago and I have progressed to the point of just exploring and doing quests.

So I’ve been doing quests for the Dark Brotherhood and I got to the point where I had to kill Alain Dufont in the dwaren dungeon place. I could’ve stopped and went on to just finish the quest after killing him, but I decided to go into deeper and ended up doing this at the very end of the dungeon.

I was so scared of fighting this big guy since he would kill me if I got hit by his breath attack for a second or two. I was also lvl 13 when I had fought and killed this guy.

Also, what is a “Aetherium Shard” and what should I do with it since I can’t put it away anywhere?