My players, after having travelled through a big Kobold empire to find a temple, finally encountered the temple, only to find it inhabited by a Dragon. They bump into the Kobold who had been tracking their progress after scouting the temple and being concerned about there being the Dragon.
The Kobold ranger outright tells them that the only reason they were allowed into the Empire to look for their temple is because the Kobolds knew there was a Dragon in the temple (even though they never told them before) and they were hoping to manipulate the players into killing it (the Dragon had set up wards that blocked out Kobolds, so they couldn't do it themselves)
The players proceeded to demand a reward in gold and trade-rights from the Ranger, who said that he could promise them an audience with the emperor and that he'd reward them for helping. Why they think this was a good idea is the topic of a second question I'll be asking.
However, this means that during the next session the players will be travelling to a nearby city to talk with the local Kobold Duke of the province that borders the players' own city (the Ranger has no intention of taking them all the way to the emperor, he has stuff to do) where he will leave the players to discuss trade rights.
This empire is absolutely vast, the players control a small city (about 1000 humans) and they basically have nothing to offer the Kobolds. (Well, slaves maybe, but I don't think the players will go for that) The Duke is also not very interested in giving the players the large sum of gold that the Ranger promised them.
However, he will be very interested in manipulating the party further to do his dirty work and maybe get them killed just for the sadistic pleasure the Kobolds will get from it.
But I'm a little stuck on how to properly portray this guy and his advisors. They are all hateful of non-Kobolds (which is something I can play well enough) but they also have to be manipulative and believable, and that's the hardest part.
The players have not seen the Kobolds do anything evil (mostly because they haven't been allowed in any Kobold town yet) but they're very aware that Kobolds are usually evil, are very xenophobic and that the only one they've really talked to has openly admitted to being manipulative towards them.
As a DM, how do I play an evil noble trying to trick the players into doing his dirty work? I don't want to railroad them anywhere, but ideally I want them to accept his offer out of their own free will and play it such that the Duke doesn't have to pay them much (or anything) in the end.