How much control do you have over a charmed creature from the Great Old One warlock's Create Thrall feature?

Question

In the Great Old One branch of Warlock, there is a Create Thrall effect, which states that if I touch an incapacitated creature it becomes charmed toward me - but it describes nothing else about the charming.

How much control do you have over the charmed person?

Most charming spells describe your limits on what you can do, such as that you can order them around but you can't order them to do something against their nature. So are there any rules that cover charming in general?

I know the basic stuff listed in the Player's Handbook, such as that charmed creatures cannot attack allies of the charmer - but does charming give any control over the charmed person?

Answer 1

Charmed is a condition, described in the Player's Handbook. The rules for that condition (and only the rules for that condition, if you're going for strict RAW) apply to anyone affected by Create Thrall.

It's also common for the charmed condition to have additional story effects. Often, unless the charmed character has immediate reason to resist, they'll be amenable to reasonable suggestions, though this at least is what you should be able to rely on even in the strictest of situations:

From the D&D Basic Rules (and the Player's Handbook differs very little):

A charmed creature can't attack the charmer or target the charmer with harmful abilities or magical effects.

The charmer has advantage on any ability check to interact socially with the creature.

Answer 2

The ability grants only the charmed condition and the telepathic link. Any "control" would need to come from Persuasion, Diplomacy, Intimidate, etc. which would be likely to be effective due to the permanent advantage. The target will not be able to escape checks, either, as long as he's on the same plane.

The power of the ability, then, is tied to the character's Charisma and skill proficiencies, while the target's resistance to control is linked to their various opposed skills.

Note, too, that while a charm person spell specifically ends when you attack the subject, that's not an effect of the charmed condition itself nor of Create Thrall. Create Thrall can only be ended by remove curse or until the charmed condition is specifically ended by another effect (i.e., greater restoration, hallow, power word heal, et al). Thus the Warlock is perfectly free to attack his or her Thrall and the charmed condition will not end.

Also note that charm person's secondary effects (the target perceives you as a friendly acquaintance, and knows and remembers that you charmed it) are also not present. You'll likely need to use some skills to get anything from the person, but unless you start ranting in his head he might not necessarily even know he's been charmed. Power wise, the ability is much closer to dominate person than it is to charm person.