The only one I found unappealing was the Sions pic.  The video of the 'dark elf' was cool to see.  I like quite a few of the names pps have listed here for your swamp creature.  I will add Arsheraugh, Swompoith, Mirishaik, and Pheamuolth.

Daemons were inspired by the ice titan from the movie Hercules weren't they?

I thought the Edar looked pretty badass, but when I read "daemon" I knew that wiry-looking thing would be all kinds of bad news. You just know they saved that name for the really dangerous ones.

This ^^

Can a fallen Emperor equip their troll(s) with Armor and Weapons? Can umberdroths be used as Mounts for certain people (maybe trolls or half-trolls)?

Edit: Just going to Reiterate that I love the creatures listed thus far: Especially the Edars, and the Umberdroths are a really close second.

I could see Umberdroths as either elite monsters used by a Soveriegn (as pets essentiall), or an Umberdroth could be used as a Sovereign's Mount. It really seems like the perfect Mount for an elite Dread-Channeler among the fallen. (like a Dread-Knight sort of Sovereign)

really love the Edars and Demons as a sort of elite warrior, and demons even as an elite politician perhaps ... like a Demon Champion usable by the fallen, for instance.

another creature I would suggest would be a Mud-troll. Usually found in the more dangerous swamps or mountainous regions, usually like to live in caves and burrows, but come out in the rain. They are small and round, shorter than a man, Bloated and Hunchback for the most part, shuffling on stubby feet, slimey and slippery skin, like to be covered in mud if possible, sometimes wait in the mud with only their eyes visible, peering out over the muddy surface (top of burrow or in a watery swamp). They are a sort of grunt troop/fodder. Not very intelligent, very rudimentary instincts, only real weapon is their razor-sharp teeth, and their tactics of swarming prey to attempt to surround them and devour them. Almost always work in numbers. A lone mud-troll will usually retreat into the swamps to look for others, but in the heat of battle often they will lose sight of the bigger picture and all throwthemselves to die in battle against a superior foe. Equipping them with simple weapons is possible but inefficient, its far better to mutate them (through magic) to give them longer, sharper claws, and faster legs ... so that they can be more effective in combat. In other words, they are the perfect Cannon Fodder for the Sorceror that invests heavily in Magic (including body alteration magic) and doesn't invest well into armor and weapons. Just give the Mutated Mudtrolls some helmets to protect from critical attacks, and send hordes of mud-golems at the enemy while you blast them with your spells. (about 100 mutated muddies(mudtrolls), and 1000 regular ones, for instance)