These have come up recently in a few online forums and groups, so now they are on my mind.
A memorable take on the creature by the late, great Steve Zieser!
Thouls are pretty well known among a certain segment of the old-school D&D crowd. They are definitely one of the weirder creations within the BX books. The theory behind their creation that I subscribe to is that some DM was trying to fake their players out with something that looked like a normal humanoid, but had weird abilities.
Despite the fact that they have an almost iconic status. I have rarely seen them used outside of a written encounter in the module B10: Night's Dark Terror.
Thoul (from Moldvay):
Move: 120' (40')
Att: 2 Claws or weapon
Damage: 1d3/1d3 or weapon
No. App: 1d6 (1d10)
Thouls are described in Moldvay as "a magical combination of a ghoul, a hobgoblin, and a troll." What this means in practice is that they look like a hobgoblin, but can paralyze you and they regenerate. They do appear as a level three wandering monster. With two potentially paralyzing attacks per round, 1d6+ of these creatures could give a low-level party a very bad time indeed. There are a couple of points to clarify, though.
- They do not look exactly like hobgoblins. At close range, there are visible differences. A party might be able to spot them and prepare accordingly (or flee!).
- Despite "ghoulish traits", they are not undead. This means that while a cleric's turning power is useless. Sleep or Charm spells can work.
- Their regeneration is only 1hp/round. While it is (apparently) not stopped by fire or acid damage, it will not revive a killed thoul.
I imagine thouls as a sort of sub-race to the hobgoblins. The description says they might be found guarding a hobgoblin king. Perhaps they are viewed as useful freaks? Who knows? As a DM, I think I would likely use them mixed in with the normal hobbos, so as the PCs work their way through the foe, there are a few nasty surprises waiting in the mix. Even though a Sleep spell can work on them, if they are among a bunch of 1+1 HD hobgoblins, the lower HD critters will take the brunt of the spell's effect. Their regeneration also means a bit more book-keeping in running them, but adds tot he scariness of the encounter.