Demons of Montporte (An Unfinished Post)

Demons Pestering St. Anthony
The brave adventurers in the Montporte Dungeon Campaign have had four encounters with demons. It is not yet clear why there are so many nasty demons are milling about. But, what is clear is that the demons of Montporte are tough. The adventurers' record versus demons is 2-2. In two encounters, the party carried the day. In the two other encounters, the player characters were fortunate to escape with their lives. The demons survived those two encounters relatively unscathed.

Demons are an ongoing project me so I am not ready to post a full stat block and description of them, but here are some basic facts about demons in the Montporte Campaign:

Every demon is unique: There is no demon "type" in the Montporte campaign. Each is unique in its size, shape, appearance and capabilities.

Demons come from somewhere else: They come from the plane of Syvyys. Unlike other extraplanar creatures, such as the fey, demons cannot travel to the plane of Aarde (the plane of Montporte) of their own volition. Demons can be brought to Aarde via summoning spells, powerful magic items, and portals/gates. 

Demons are tough: Demons are difficult to hit in combat and they have loads of hit points. They also are highly resistant to magic, meaning that they gain a special saving throw versus every magic spell. If they fail this special magic resistance saving throw, they still get a saving throw for those spells that allow for saving throws. 

Demons can hurt you: Demons are dangerous foes in combat. They do a lot of damage and often have special attacks as well. 

Demons can really hurt you: When a demon kills a mortal from the plane of Aarde, the soul of that mortal is ripped asunder and destroyed. The person cannot be resurrected, raised, reincarnated, wished back to existence or otherwise brought back. They are gone for good. That's a real buzz kill.

Demons don't like it here: Demons really don't like coming to the plane of Aarde. It ticks them off. Woe to the summoner who loses control of a demon. A demon milling about on the plane of Aarde is an angry demon milling about on the plane of Aarde. 

Demons don't move around much once they get here: Once a demon is summoned, it must be compelled to move, otherwise it will simply stay in place until someone takes/sends it back to Syvyys. In the meantime, see the point directly above this. Demons are not happy campers.

Don't think or talk about demons: There are recorded instances of demons being summoned merely when they are mentioned in casual conversations by the mortals of Aarde. Even thinking too much about demons can be a risky activity. This is the primary reason why there is no published literature about demons. Plenty of scholars start a demon treatise. None of them fi