Yeah , as mentioned above , best way to stop respawns is to dig a pit and get him to fall in. Then he can't get you and can't respawn. Worst is when drakes come along and kill him slowly , then he respawns.

A friend and I dug a pit the used the the iron grating to cover it over then built a mountain base around it , so that he was always there just under the floor , completely harmless. We eventually popped a hole in the mesh dropped in a couple dragon eggs and sealed it back up. this way he was illuminated.

*Edit - if you really want to get crazy and your are playing on a server with group of people , you can pop a hole in the mesh , then cover said hole with a lox skin rug.... one way in no way out.