Tonight I have finally played my first Warlock. I chose the Great Old One Yog-Sothoth as my Patron and, while playing the game, my Drow Warlock (who took the boon of being a Gold Dragon who was too vain and proud and got tossed into a weaker body), while being stealthy on an random encounter in tonight's Encounter game ended up using his level 1 ability of Telepathy. No intention here for spoilers, but hey I'm giving you a heads up: Spoilers.
On my next attempt when the group fails it's stealth check, I rolled an overall 24 on my Deception check and the DM gave the new Kobold an Advantage and, somehow, a major bonus despite it being within his religion to sacrifice lesser beings like Humans while there were a majority of Kobolds as compared to Humans (and a Winged Kobold too).
There's a spoilers tag. Just enclose it in [ spoilers ] and close it with [/ spoilers ] ...
The proper skill check in a situation like this is an opposed contest between your Charisma (Deception) check and the Kobold's Wisdom(Insight) check. Each of you roll a d20 and add your modifier and whoever gets higher wins, ties go to status quo in this case I would say would be not believing you are Tiamat. Kobold's have a -2 wis check and are not proficent in insight.
If the DM wanted to make it harder (understandable as he hardly wants you winning all your battles this way), he could easily say that you can only use your Telepathy on one Kobold at a time, and that it takes a full action to do so (while the rest of the Kobolds are attacking you). Kobolds have all of 5 hit points, so while you could kill it with a single good weapon attack, if you want to practicly kill it (with minor bonus from it helping you) with an opposed skill check that might be much harder then just shooting it (depending on how the dice roll), that would seem to balance out. You wouldn't be nearly as effective latter when things get higher wis scores.
DM's shouldnt give advantage or disadavntage or bonus/negatives without saying why, there should be at least a somewhat reasonable reason why they are less likely to believe you. Maybe someone you tried this trick on earlier but it didnt work and they got away and told this Kobold to watch out for it. But there should be a reason.
Oh the other thing is while you do succeded in what you are trying to do, that doesnt neccesary mean you get the outcome you were trying to get. Maybe this Kobold really believes Tiamat is speaking to him, but that just scare the @#$ out of him and he runs away screaming rather then doing what Tiamat wants. Or maybe he runs off to the nearlest leader to inform him of what Tiamat requests that they kill all the cultists thinking that Tiamat means they must kill all the cultists not just the ones in this group (that leader may not believe him though).
I should have noneted: you need to remove the spaces from those spoiler tages. I did them that way so you could see them. Otherwise they would have just tagged my post. 
Agreed on that. I wasn't claiming to be Tiamat, just that it was Tiamat's order to kill the cultist. Considering that Humans are considered inferior to Kobolds and, more importantly, there were more Kobolds and a Winged Kobold present and none of our group had been discovered yet... I had expected to get to the second Kobold and have it succeed without our group having to confront them. Yes, I did not intend on doing this more than this encounter and, considering that the first Kobold began to attack the Cultist before we were present, I had hoped for a Return of the King moment with pitting the Kobolds against the Cultist as a distraction. In truth, I had almost used Dancing Lights instead, but figured this was more interesting. I did try and use a full action to Persuade him afterward to surrender after thanking him for doing Bahamut's work and all of his Kobold friends and all but one cultist were dead, but unfortunately I failed on my check against him.
Also, the DM did not do an Insight check but somehow he did an opposed Deception check (I don't know why, but that is what he did) and despite everything, my next roll being a 24 still failed versus it (I rolled a 19 + 5). I do agree on the Wisdom (Insight) check opposing me and, perhaps, a bonus given but agreed, there was no reasoning why, nor any attempt to argue with my thought on how they would react considering my character's Boon.
I don't know why, but the spoilers tag doesn't seem to work for me.
Its singular not plural
text inside spoiler
That's my fault. I was typing while my kids and I were singing along to a Leapfrog video.
Thanks. Alright, fixed.
Honestly, the rules in the PHB are exceedingly light when it comes to social interactions. And that's what's really going on here, a social interaction check that has little to do with Telepathy. Given everything, I would say that most of the answers are probably going to be coming out in the DMG.
The rules for contest are on page 171 of the PHB but they don't exactly mention this kind of situation.
I'd probablly run it as a Deception check against the kobold's passive insight as the DC. I haven't seen the Kobold stat block yet, but I'm guessing this will be a 9 or 10 based on older editions Kobolds.
Of course, I'm also the sort that only wants to roll attack rolls for the monsters, so there's that.
I think the idea here is that Advantage and Disadvantage can be used as a situational conditioner. Although by the rules of the new system, you wouldn't get Disadvantage AND a static negative modifier. In fact, I believe static negative modifiers are pretty much a non no in 5th ed except in rare circumstances.
As for the why this happened, I'd judge that the first kobold got caught by surprise and followed blindly. His fellow kobolds saw this strange happen out of the blue, and the next kobold who heard the voice in his head likely knew something might be fishy, hence the Disadvantage. Remember, it's just voices in it's head. There's no actual magical compulsion at play.
It's kinda hard to tell right now, without the DMG offering the rules on how to handle these kinds of interactions, but in my mind, it makes sense.
I think the DM ruled appropriately; deception vs. insight. Since you're trying to fool the kobold into taking direct action at great risk to itself, the advantage to the insight check was warranted.
If I were DMing, I would rule that when a warlock communicates telepathically, a hazy image of the warlock appears in the person's mind... that way you can't be some totally mysterious, unseen voice. I'd still let this work as it did... part of the deception would be disguising your mental image as a messenger from Tiamat or something,
Perhaps a silly question - The great old one telepathy for Warlocks - does this allow for two-way communication? I understand that the creature can understand the Warlock, but can he read its thoughts? Seems like it's quite powerful if so - after all Monks get all languages much later!
The way I run stuff like this is Deception vs Insight. I'll hear what the player has to say and decide to give them advantage/disadvantage (or neither) depending on how believable/outrageose the claim is. Then I decide the outcome on the difference in the results. Like a degree of how much they believe you, or don't. So in your case 1-4 might be, "Tiamat is that really you?" *waits for response* 5-9 might be, "I hear you my Queen, I will tell my fellows of your command." 10-14 he might not question and attack immediately. 15 and over he'll attack while screaming, "Tiamat says you all die today!" like a you would expect a religious zealot to do.
ABGaming wrote:
My variant human Warlock has this with the Actor feat. It's great fun to have them think it's just their subconscious talking because I'm using their own voice. Jedi mind trick status. 
Danny_Montanny wrote:
Danny_Montanny wrote:
I know you've read p. 110 (Player's Handbook) and if you have to see your subject to communicate with h/h/it, s/he/it would also be able to see you under most circumstances (see comment #13). A well-chosen patron, I must say! Perhaps my style is so different, but it seems to me that the most direct approach would involve using your own knowledge of the subject, in order to address it in such a way as to persuade it that s/he/it, h/h/itself, is insane.
I assume it's two-way communication as if you were speaking to the target; you can receive consciously replied thoughts but can't "mind scan" or "mind probe".
It would be a Charisma (Deception) check vs. an Wisdom (Insight) check. I could easily see giving you disadvantage or, better yet, give the kobold advantage depending on the situation, especially if trusted religious authorities (like a priest or any true dragon) have already okayed the alliance. If "God" told you to do something dangerous and out of character out of the blue, you'd probably be a little skeptical and might ask some small confirmation. You wouldn't want to anger the deity, but you aren't going to risk your life for some random voice in your head, especially if you know for a fact that you lived in a world with various kinds of magic. The fact that this alleged divine revelation comes right as they find an intruder of the famously magical drow race who may or may not have possessed trappings of a caster only makes it more suspect. This easily qualifies the kobolds for advantage.
Now if you telepathically contacted a kobold while hidden and gave them this revelation, and the kobold was a Tiamat-fearing zealot who was already untrustworther of the humans, then it would have a much better chance of recruiting a sabatour.
This is a classic dm judgment call. I would also only allow one way communication with an at will ability such as this. I would hsve given the kobold adv on the save from the outset, as it is highly unlikely tiamat would be sending a message to a particular kobold to kill his own allies, out of the blue... or I would roleplay a weirr mental breakdown of the kobold if he fell for it, I wouldnt have him immediately attack his friends bec a voice in his head suggests he do so.