巢作之龙

The setting is Middle Ages Europe style.

A dragon male (the protagonist) must, in order to marry, amass a lot of treasures and wealth in his dungeon. For that reason, the protagonist went alone and lived in an area where human lives, constructed a huge nest and started amassing treasures. However, soon after the nest got built, gallant heroes wanting to exterminate dragons, townspeople that see the dragon as a nuisance and adventurers and thief out to get the dragon's treasure came.

With this, he couldn't gather treasures at ease. Therefore, the protagonist hired monsters, added traps and threatened the neighboring area to not approach his nest. With his nest's defense strengthened, the protagonist started amassing wealth. He searched for a gold mine all over the place, started farming, deforested the forest to build drawers out of it. Of course, the foolish invaders that's successfully repulsed are stripped of all their possessions. Incidentally the women are used as sparring partner to gain experience for the honeymoon.