How to get doppelgangers on a train? (dnd 5e)

[Pinjata]

Well, not an actual train. To make them "work for you". Say you are an adult chromatic dragon with significant amount of gold and your own small mercenary army. You want to expand into all merchant businesses in the region along with all the guilds, including thieves guild and asssassin guild. In order to do that, doppelgangers might be real nice. Now, according to 5e lore, doppelgangers are reclusive creatures, working on their own. Say you manage to get some sort of item with True Seeing for you and some of your henchmen. Now you can spot these doppelganegers. How do you convince them to work for you? How do you make them loyal?

[Mutazoia]

Well, not an actual train. To make them "work for you". Say you are an adult chromatic dragon with significant amount of gold and your own small mercenary army. You want to expand into all merchant businesses in the region along with all the guilds, including thieves guild and asssassin guild. In order to do that, doppelgangers might be real nice. Now, according to 5e lore, doppelgangers are reclusive creatures, working on their own. Say you manage to get some sort of item with True Seeing for you and some of your henchmen. Now you can spot these doppelganegers. How do you convince them to work for you? How do you make them loyal?

"I am a Dragon. I found you once, I can find you again. Cross me and I eat you. Now get to work."

You could also use a Geas to compel them into service and keep them from double crossing you and/or escaping.

Oh...and....

"I'm tired of the mother freaking Dopplegangers on this mother freaking train."

There...now THAT is out of the way.

[Pinjata]

What kind of a dragon reveals his true form to be just a week later killed & looted by appropriate level adventurers?

[Mutazoia]

What kind of a dragon reveals his true form to be just a week later killed & looted by appropriate level adventurers?

One that is sufficiently confident in his power that he don't really worry about a pitiful group of mortals who probably won't live through neither the horde of underlings, nor the legion of traps both magical and mundane to even get close to his lair, even if they did some how find out what one of his polymorphed forms looked like.

[Gastronomie]

What kind of a dragon reveals his true form to be just a week later killed & looted by appropriate level adventurers?

According to the descriptions of the Character Level Tiers in the DMG, characters capable of defeating a fully mature dragon are “true paragons in the world”, and the fate of nations or even the world can depend on their quests. They have fortresses and parcels of land, as well as guilds or temples or armies under their disposal, and you know, generally you’re not gonna expect four or five or even six of these goddamn celebrities to come killing you in a team. You’d be damn surprised if the world boxing champion wearing the Iron Man suit, as well as the boss of the world’s Mafia, backed up by a Nobel award-winning scientist and a Catholic cardinal who’s scheduled to become a Saint after his death all come raiding into your evil hideout. Because that's basically what characters of that level are supposed to be, in-game wise.

Most doppelgangers would prolly agree to work for a dragon if threatened. Or you could simply have a doppelganger say he'd work for anybody if given the money, laughing at the other doppelgangers for not seeing the profits of working under said dragon. First set up the scene, and then give it reasoning.

[Pinjata]

nice and neat. I want crucial characters of my setting to be water tight as far as logic goes.

[GloatingSwine]

Same way you get anything to work for you. Offer them something they want.

So what do your doppelgangers want? Do they just want to infiltrate society and live unnoticed? Well it turns out your dragon already has a group of employees that can arrange openings in certain positions in society that a doppelganger can neatly slip into.

I mean that's probably the biggest risk in a Doppel's infiltration, the actual acquisition and insertion. Having a well resourced group of mercenaries helping with that is a win-win scenario. The Doppelganger gets his nice safe cover identity and the dragon gets a well placed individual who owes him a favour.

(PS this could have happened decades ago, inserting the assets at lower levels in the organisation and allowing them to rise through its ranks to trusted but not necessarily critical positions where they can steer events without risking exposure).

Double points if the Doppelgangers are playing their own game and wanted to take over the secret levers of power anyway because then there's narrative tension possible between the dragon and its tools.