Need help finding a wad

I kind of remember playing a ZDoom wad in 2005 or 2006 in a sort of "Defend the castle" setting. The player defends a castle front of sorts by killing multiple waves of imps. Each time, a new wave of imps and black imps (Nami or Void Dark imps, don't know) appear and you kill them. I may be mistaking it for a simple fort to defend, but I remember these parts of it. This was before I began using Skulltag.

I played it in single player, but maybe it is multiplayer compatible as well.

Could it be this one? :P
http://www.doomworld.com/idgames/index.php?id=11891

I played it a while ago and thought it was pretty fun.

That sounds like Imp arena.