I'm trying to look up an old item my character had pilfered off some demon or devil that involved an 'Infernal Trident' that had special properties. When an attack lands, it causes the target to make a CON save or become infernally wounded. I wish I had my old sheet, would anyone have insight on what this may be? We ran into it during the Tomb of Annihilation.
What Demons/Devils have trident attacks
dnd-5etomb-of-annihilation
Related Solutions
Devils and Demons get along like a house on fire ...
... people screaming, running around, flailing, dying etc.
In accordance with their lawful alignment, devils obey even when they envy or dislike their superiors, knowing that their obedience will be rewarded. The hierarchy of the Nine Hells depends on this unswerving loyalty, without which that fiendish plane would become as anarchic as the Abyss. (Monster Manual).
Devils are the embodiment of evil: specifically the type of evil implemented by large bureaucracies. People can be tortured and made to suffer but only when a 37B form has been completed in triplicate and appropriately filed. Ok, not really, but they are the embodiment of organised evil. They therefore have a lot in common with Angels who are the embodiment of organised good, however, angels and devils do not work together.
Demons are the embodiment of chaos and evil- engines of destruction barely contained in monstrous form. Possessing no compassion, empathy, or mercy, they exist only to destroy. (Monster Manual)
People can be tortured but only if the demon wants to: and it always wants to. They are the embodiment of random evil. Demons and devils do not work together - indeed, demons and demons do not work together, they are too individualistic.
That is not to say that a particularly cunning and clever devil couldn't utilize demons in their plans but such circumstances would usually involve deceit rather than cooperation. Demons, of course, don't make plans.
Earlier editions of D&D specifically had demons and devils locked in an eternal Blood War, however, 5th edition has, as yet, not given us any information about it.
It's not specified.
D&D 5th edition's Mordenkainen's Tome of Foes is the first sourcebook to reveal that the Ruby Rod was forced upon Asmodeus by Primus, and that devils obey their contracts out of fear of the rod's curse. It's not specified in any other 5th edition book, and the relevant sourcebooks of earlier editions make no mention of this curse either.
D&D 3rd edition's Fiendish Codex II: Tyrants of the Nine Hells defines Asmodeus, the Ruby Rod, and the rules around mortals making a pact with a creature. On page 23, regarding Faustian Pacts:
Though benefits of extraordinary value can be offered in a Faustian pact, the devil preparing it always tries to achieve the deal with a minimum possible expenditure of resources. Once the soul is securely damned, the negotiator often arranges—usually through servitors—to bring about the signatory's untimely death.
Page 25 describes what happens if a soul goes to Baator and demands the right to adjudication on the grounds that their rewards were not granted, or that the mortal was coerced or magically compelled:
The judge, usually a pit fiend, listens dispassionately to both sides and rules, as a lawful creature must, according to the law.
If the mortal wins, their soul goes free and may be restored to life with raise dead as normal. Notably, there's no mention of any curse or penalty which affects the devil who made the pact.
Asmodeus and his Ruby Rod are detailed in this book (p.155-157). There's no mention here of the rod's origin with Primus.
In AD&D 2nd edition's Planes of Law, it's suggested that devils obey their contracts because they are experts at creating and exploiting loopholes in contracts, so the contract is always in the devil's favour (p.20):
They'll cut a deal with any berk they can, and woe to the sod who agrees to their terms — and dire woe to any sod who thinks he can skirt the agreement! The baatezu've been making deals since before most Prime worlds cooled from the heat of creation; they've learned just about all the loopholes.
Best Answer
You’re likely thinking of either a bearded or a horned devil.
The bearded and horned devils are the only monsters with an “infernal wound” mechanic. The horned devil in particular appears to carry a bident. However, it should be noted that there is no official player-facing magic item that has that ability, so it is quite likely a homebrew magic item the DM created as a reward for defeating the devil(s) or something like that. Both of these devils are featured at least once in Tomb of Annihilation.
Or maybe a Nycaloth?
The nycaloth has a similar mechanic called a “fiendish wound” that works essentially the same way. I mention this guy because a statue of a nycaloth appears in Tomb of Annihilation, which may lead a DM to insert one into the adventure.