Voxel M.R.T.
You like RTS and you always wanted to walk through the castle you just built?
Congratulations!
I got exactly what you want!
Voxel M.R.T. combines RTS with RPG, it is basicly a game about building a castle and defending it against npcs or other players plus you as the ruler play your own character. You can help gathering resources, building and fighting.
You play as a rpg like character (Like archer, mage, etc.) and try to lead your army to success. In order to get an army you need to build a good economy to give your people important things like food and beer. Let your villagers work for you or help them, what ever you like. What kind of ruler are you? Once you and your people survived long enough and you and your army are leveled up nicely, you can fight back and destroy enemy spawners and/or the other players and win the game.
You can customize the games difficulty by changing settings like peacetime, spawnspeed and strength of the enemies.
There is a level editor in the game, so everyone can create custom levels and sare them with other people.