It's difficult to show everything with only 6 additionnal images, so I add some other screenshots here:

some addtionnal wireframe from the same views:

Originally, I chose another view for the render; here are some previous renders with this previous view, when I was searching for the best linghting (without the stairs under the pillars, but with walls in the throne room):

Finally, I abandonned the walls because they darkened too much to room. I also added a red point light behind the Darklord, just between his back and his throne, in order to make him more visible:
 

And some white point lights in the room to enlight the pillars ans the ground:


And finally, I added emission settings for the dragon eyes:

But after that, I wasn't satisfied by this view, then I searched for a better one:


Depending on the view, I also tried different positions for the dragon:

And I show you here the renders corresponding the the first and third screenshots from my first comment:

(the render above is one of my favorite ones, actually )