So I was bored and decided to give it a whirl.
Monsters are now able to be spawned by command. The version I coded is VERY poorly done and most of the values are hard coded to avoid messing things up myself.
I did it in CoEmu but it should be fairly similar.
Go to where your source controls monster spawning (in coEmu it's MonsterSpawn.cs. It should be a very obvious section regardless of source)
Then just copy the required section over to where your source handles player commands in a way that will allow you to change what you want (map, x, y, mobid, number of mobs)
In CoEmu the main line that actually controls the final spawning was a little something like...
ConquerPacket.ToLocal(ConquerPacket.SpawnMonster(M on.UID, MobInfo.Mesh, Mon.X, Mon.Y, MobInfo.Name, Mon.CurrentHP, Mon.Level, Mon.Direction), Mon.X, Mon.Y, Mon.Map, 0, 0);
ConquerPacket.ToLocal(ConquerPacket.MobSpawnEffect (Mon.UID, Mon.X, Mon.Y, Mon.Direction, 131), Mon.X, Mon.Y, Mon.Map, 0, 0);
Interlocked.Add(ref SpawnNumber, 1);
Note that the Interlocked.Add(ref SpawnNumber, 1); is just a section that was in the monsterspawn.cs file that controls if it should start spawning new ones (for ever monster it spawns it says "hey, I finished spawning this one. Do I need to spawn another?" basically controlling how many should be spawned. I just copied basically the entire section out of there for testing purposes so I haven't tried removing it. In mine I just set it to 1 and let it be.
For any sort of quest monster I'd strongly suggest adding a timer of some form to control respawn. if not you would have to summon it manually via command every time you want. You could always use a combination of adding to the database and reloading it if you wanted a recurring spawn though I suppose.
ooh and just cause I am extra bored. Screenshot
They move, attack, die, drop items etc all like normal mobs should via cmd.