Alright, sure. How's these:

- The dragon lives in a huge castle in the highest point in the city.

- He has multiple mates, including female dragons and possibly even other species. And yes, he would have children, who are smaller than he is, but still powerful. 

- If he has mates from other species, he might have half-breed children, who could also serve as enemies, possibly as commanders in his army. 

- He's a big red dragon that breathes fire. Not very original, but it works. :)

Just some ideas.