Cleric options for communicating with undead

Question

The party is in the classic module D3, in the drow city of Erelhei-Cinlu, seeking information about a suspected planned invasion of the surface world. For several days they have been in the city, gathering information while evading extensive surveillance by various factions. The party is using seeming, disguise self, and mundane disguise kits when out and about to constantly change their appearance. When resting, they are in a magnificent mansion covered by a private sanctum. The different noble houses as well as the Fane are aware of their presence, but so far have been unable to get reliable intel on their actual identities, reason for being in the city, and whether or not they are being secretly sponsored by one of the noble houses.

After several days of cat-and-mouse, things have come to a head and the party was attacked as they emerged from the hiding spot of their mansion. They won the immediate combat but an alarm has been raised and we ended the last session with them realizing that they will need to flee the city.

While I can't be certain, it appears that in their flight they may leave behind the body of a minion who was killed in the fight as well as a drow who was zombified several days ago through finger of death and who has been used ever since as a door guard for the mansion. If either of these are recovered by the Fane they could be a valuable source of intel on the identities, motives, and patrons of the party if they could be made to talk.

Speak with dead on the minion's corpse will not reveal much because he is loyal to the party and will resist the questioning.

Killing the drow zombie and casting speak with dead on the corpse will get a willing spirit, but one who does not know much as the party killed him in a street fight while they were under disguise.

If there was some way of communicating with the zombie ("understands the languages it knew in life but can't speak") that would be most useful, as it stood around for several days, saw the true identities of party members, and overheard some of their conversations. Detect Thoughts won't work on this zombie, both because it doesn't speak and because it has an Int of 3. Telepathic Bond would accomplish what is needed, but it is a 5th level wizard spell, and I am reluctant to place a 9th level arcane caster as working directly for the Fane. In this setting, the Fane is dominated by female divine casters, and male arcane casters are of lower levels or are members of the noble houses. Another possible solution would be to summon some type of fiend with telepathy, and use them to communicate with the zombie. Lloth values self-sufficiency, but the yochlol demons available to her clergy don't have telepathy, whereas the shadow demons summoned by the noble male mages do.

The Fane would prefer to gather this information in-house, without sharing it with the male wizards of the nobles. Is there a way for a divine caster to achieve this, either through a spell, class or subclass feature, or magic item?

Is there something that would either (1) allow a divine caster to communicate with the zombie, or (2) force the spirit of the minion to talk?

Answer 1

Raise the minion

If I'm the evil cleric, I'm just going to raise the minion and then use mundane tactics. I mean, just how loyal is the minion? Once raised, if the minion can't be flat out bought, then surely they'll eventually succumb to some sort of influencing magic.

Planar ally comes to mind.

. . . while a fiend might demand a living sacrifice . . . .

"Hey, minion, welcome back to the land of the living. Come over to the dark side and wealth and power will be yours¹. If that doesn't appeal, well, say hello to my pit friend here. They'd like to make your acquaintance."

yochlol have detect thoughts

What, don't want to let your clerics use planar ally? That's okay. The yocholol have detect thoughts in their stat block. Detect thoughts won't work on a zombie, but it will work just fine on the raised minion.

The reluctant soul

What's that, the minion's soul isn't willing to be raised? Wow . . . that is some loyalty.

Perhaps trickery will need to be called for. The DMG says about Bringing Back the Dead:

A soul knows the name, alignment, and patron deity (if any) of the character attempting to revive it and might refuse to return on that basis.

Perhaps the Fane have in service some cleric who can stand in as an intermediary. While the soul might refuse to be brought back by a cleric of Lloth, perhaps a cleric of the Svirfnebli, the Kuo-Toa, or some other sect known to the drow would be willing to do it (for suitable payment or coercion), and would pass the post-mortem sniff test of the soul being pinging for resurrection.

Okay, it's a long shot, but the dead minion's soul only knows the cleric's name, alignment, and deity, so it's not completely out of the question that they might take a chance to return to life.

Raise the minion as a wight

Or, use create undead to raise them as a wight.

Wights possess the memories and drives of their formerly living selves. They will heed the call of whatever dark entity transformed them into undead, swearing oaths to appease their new lord while retaining their autonomy.

Don't be too worried about the wight's "autonomy". Sure, the wight's description says "autonomy", but it also implies some sort of allegiance to "the dark entity [who] transformed them into undead" (the evil cleric raises their hand), and create undead says things like:

each corpse becomes a ghoul under your control

you can mentally command any creature you animated with this spell

you decide what action the creature will take

you can issue a general command

[t]he creature is under your control

Does the cleric have perfect control over the "autonomous" wight? No. But they have a lot of control. The wight is intelligent. It has sworn oaths to the evil cleric ("dark entity"). Create undead is exerting control over it.

All of that, and I think you ought to be able to peel them like an onion. But if you don't think so, that's what's important. And, fair enough, there's plenty of discrepancy between the text of create undead and the description of the wight, leaving a ton of DM adjudication just to make the spell work (like that's never happened before). It's pretty clear the writer(s) of the spell and the monster didn't carefully rectify the two descriptions against each other.

After all of that, even if the wight is uncooperative, detect thoughts can probe pretty deep, given a captive target and time.

Kill the zombie anyway

I mean, speak with dead is cheap. Maybe there will be some useful information.

And commune the heck outta those PCs

Every cleric 9th or above can cast commune once a day.

You contact your deity or a divine proxy and ask up to three questions that can be answered with a yes or no. You must ask your questions before the spell ends. You receive a correct answer for each question.

Surely that will help fill in any gaps left by the minion and zombie.

Don't feel restricted by the restrictions the PCs face

I know, I know. It sometimes feels like cheating to let NPCs use resources not available to the PCs. But it's not. The DM has to represent the whole world. There is plenty out there beyond the reach of the PCs, at the very least, they don't have time, they're busy adventuring. And your evil clerics have had centuries to perfect their art.

^{1 - in suitably small quantities, restrictions apply}

Answer 2

They can summon a Glabrezu

To start off, if I were the DM, I would assuredly do what @Jack suggests, and turn the villain into a wight with create undead, or if important for the story, let them have some way the player's wouldn't.

But if all you need is communicating with the Zombie, and you want a by-the-book way for that, high level drow priestesses like the Drow Matron Mother from Monsters of the Multiverse can summon a Glabrezu demon, and the Glabrezu has telepathy. The Matron Mother herself is of a house, not of the fane, but clearly is a Lolth priestess. If she can do this, so should another high level Lolth priestess, like the fane's high priestess

Although matron mothers command great power, that power depends on maintaining the Spider Queen's favor