In earlier editions, I can't see that they've ever been given a name. Best info on them is in Forgotten Realms Adventures with a bit of extra stuff in Polyhedron #60.
Only named part of Mulman army are Hawks - elite unit used mainly for spying and cover ops. In Cloak&Dagger p.45 you have power structure in Mulmaster - leaders of army are called Battlemasters and there is 8 of them. One have command over Hawks, at least 1-2 will be commanding navy and rest will have land troops. One will probably command city defenses and watch, other will control patrols around the city and the road south (mentions of their patrols as far as Maskyr's Eye). One should have cavalery and last 2-3 will command foot soldiers (1 quartermaster, 1 heavy infantry, 1 conscipts and light infantry). Remember that there is active slave market so they have plenty of cannon fodder available at moment notice. Also they can use Orc mercenaries but I suppose they will not keep them longer than needed. There are wyverns around so they could have some aerial support on those.