abyss devil

"abyssal devils are the most patient of the devils, they blend into the darkness of their native pits and prefer to strike unseen. just like the shadow imp, their lesser counter part, they possess power over dark magic. however the abyssal devil possesses far greater mastery over it and is able to summon shades from the land of the dead to haunt the living. or leech strength and vitality while stalking their target. these devils are almost as durable as red devils, and share their resistance to fire and poison. like shadow imps, the abyssal devils are able to stay submerged under water pretty much indefinitely, why the imps, fiends and devils of the abyss all share this ability is a mystery."

the Red Devil

red devils are perhaps the most arrogant of the devils, each of them a capable pyromancer akin to the skill of a master. while durable as ten armored men. red devils reside in the wastes of pandemonium as well as the infernal waste, and boast a near immunity to fire and flame and a strong resistance to most poisons. the boundaries that keep devils from the mortal world are strong. and thus few demonologists would find themselves capable of summoning such a creature. Summoning devils is ill advised, where imps and lesser demons can already accomplish all that one may summon infernal creatures for. the red devil in particular is the least cooperative of the devils, and thus binding such a creature to ones will is an undertaking that is decidedly not worth pursuing .

the pandemonic devil

 the pandemonic devil is a creature of the wasteland in which the infernal capitol is seated. the pandemonic devil wields magics of foulness and disease. which tells us scholars that it is no doubt among the most vile creatures of hell.
 
 as it all demons and devils boast an immunity to diseases we can only assume that the pandemonic devil was specifically conceived by the lords of hell to serve not in the infernal struggle as a soldier, but rather to serve as an agent in the living world.
 
 to spread infernal foulness and to afflict the hearts of man, thankfully few mortals posess the power to summon such a creature in the flesh. and those few who do, didnt come that far by being careless with their rituals.