The Horn of Seven Hells (WIP)

[Gwaednerth]

I have a general idea for a high-level intelligent cursed magic item that I'd like some help fleshing out.

The general idea is that the Horn of Seven Hells works on the same general principle as a Horn of Valhalla except that it is both more powerful and more dangerous.

Physical description:
This long, curved horn appears to have been torn from the head of a Pit Fiend. Carved with ever-shifting infernal runes and pulsing with power, the horn seems to be straining against the confining bands of silver that confine it.

Powers
The horn can play eight different notes, each of which summons forth souls from a different part of Hell. While these spirits are useful, they also bear a considerable cost to the unwary user.

Rather than just summoning barbarians, each note summons a different class (except the eighth note). So far I have barbarians, representing souls desperate to escape Hell, paladins representing those who were good but are now on the brink of becoming truly, irredeemably corrupted, rogues representing people who see Hell as an opportunity for self-advancement, wizards representing those who thought themselves clever enough to outwit the devils and get the best of an infernal contract, and clerics representing heretical priests who preach the Path of Asmodeus.

Each summoning also poses a danger though. Some of these I have more fleshed out than others.
Barbarians who slay enough creatures should be returned to life but should be somehow transformed. I'm not sure exactly how though.
For the paladins, every hitpoint they deal should be dealt to them as well. If this retributive damage drops them to 0 HP then they transform into erinyes devils that set about corrupting as many people as they can and torturing those they cannot corrupt.
I'm not sure about the rogues.
The wizards get will saves or maybe a contested intelligence check every round to break free and if they do they should gain tremendous power as the result of their bargains, but I'm not sure what form that should take.
I don't have a mechanic for the clerics, but I feel like they should summon an apostate devil if their danger triggers.

The eighth note, when played, opens a gate to Hell through which anything that so wishes may cross over. If the horn-blower speaks the name of a particular devil before blowing the horn, it has a chance of summoning that particular devil or at least an underling of that particular devil.

The horn is intelligent. It views Asmodeus as its only true master, and seeks to corrupt anyone who holds it onto the path of lawful evil. In the hands of a powerful LE individual, it seeks to expand that person's power before finally betraying them to the legions of Hell.

I need two more classes that can be summoned by the horn and I need help on the dangers of each class.

[JoshuaZ]

I have a general idea for a high-level intelligent cursed magic item that I'd like some help fleshing out.

The general idea is that the Horn of Seven Hells works on the same general principle as a Horn of Valhalla except that it is both more powerful and more dangerous.

Physical description:
This long, curved horn appears to have been torn from the head of a Pit Fiend. Carved with ever-shifting infernal runes and pulsing with power, the horn seems to be straining against the confining bands of silver that confine it.

Powers
The horn can play eight different notes, each of which summons forth souls from a different part of Hell. While these spirits are useful, they also bear a considerable cost to the unwary user.

Rather than just summoning barbarians, each note summons a different class (except the eighth note). So far I have barbarians, representing souls desperate to escape Hell, paladins representing those who were good but are now on the brink of becoming truly, irredeemably corrupted, rogues representing people who see Hell as an opportunity for self-advancement, wizards representing those who thought themselves clever enough to outwit the devils and get the best of an infernal contract, and clerics representing heretical priests who preach the Path of Asmodeus.

Each summoning also poses a danger though. Some of these I have more fleshed out than others.
Barbarians who slay enough creatures should be returned to life but should be somehow transformed. I'm not sure exactly how though.
For the paladins, every hitpoint they deal should be dealt to them as well. If this retributive damage drops them to 0 HP then they transform into erinyes devils that set about corrupting as many people as they can and torturing those they cannot corrupt.
I'm not sure about the rogues.
The wizards get will saves or maybe a contested intelligence check every round to break free and if they do they should gain tremendous power as the result of their bargains, but I'm not sure what form that should take.
I don't have a mechanic for the clerics, but I feel like they should summon an apostate devil if their danger triggers.

The eighth note, when played, opens a gate to Hell through which anything that so wishes may cross over. If the horn-blower speaks the name of a particular devil before blowing the horn, it has a chance of summoning that particular devil or at least an underling of that particular devil.

The horn is intelligent. It views Asmodeus as its only true master, and seeks to corrupt anyone who holds it onto the path of lawful evil. In the hands of a powerful LE individual, it seeks to expand that person's power before finally betraying them to the legions of Hell.

I need two more classes that can be summoned by the horn and I need help on the dangers of each class.

What edition is this for? If this is 3.5 or 3.5 compliant then warlock would be an obvious one for people who have made a contract with hell with their eyes wide open and knowing the consequences.

Also, I'm a little confused on the summoning system: is it literally summoning a wizard from somewhere in the world? I think that most of the time summoning is interpreted as summoning archetypes most often or something like that.

[Gwaednerth]

What edition is this for? If this is 3.5 or 3.5 compliant then warlock would be an obvious one for people who have made a contract with hell with their eyes wide open and knowing the consequences.

Also, I'm a little confused on the summoning system: is it literally summoning a wizard from somewhere in the world? I think that most of the time summoning is interpreted as summoning archetypes most often or something like that.

It's for Pathfinder, so that's an option.
It works like a Horn of Valhalla. The original creates constructs imbued with the spirits of dead warriors. I don't think these should be constructs, because I want them to have a full ability score array, but I like the idea that these are actual spirits of real people, though the manifest in a sort of archetypical way. So if a non-wizard tried to cheat the devils, they'd still be summoned as a wizard, sort of like how devils come from souls of people who have similar vices, even if their powers are entirely different.