The Tibeaux Effect: Sailor's Stories and High Charisma.

Nirrum views Grand Tortuga's Recent Monarch as a Madman and Political landmine
I, on the other hand, see him as a fitting end to such a complex governmental structure

 "Really? It wasn't so hard to cross the Dragon Coast after we plundered the citadel of the undead in Konia which lead to us running from an elven king across ganglegrove where we were consumed by a ship eater that we barely escaped from before meeting one of the creators of the plane who gave us this dryad (my cook, I might add) here to help our quest to recover the Mystical demon bones. Though I will admit, even with the dryad, the quest has been a little bumpy. We've had to defeat a sandstone god on the way and BOY that was tough, but the eye of a deceased lovecraftian horror was a fitting reward and let's be honest, the ancient blue,black, and green dragons that harassed us along the coast were nothing compared to the slaad invasion we stopped in drakenhearth before coming here. What? The Unicorn we used in the assassination of Memory Jaquy? I must have missed how we picked it up in Jianok Sio, the land of giants before the Ganglegrove part as part of a quest from a Storm giant.

-Fleet King Lazarus Honore Dorian Tibeaux-Avisen Bruchev and a whole bunch of other fun factors mixed in with that
 The Tibeaux effect is simple. Put adventurers through enough and they're going to have something to talk about. Things that are of cosmic scale that they fell nose-first into because they were at the right place at the right time and capable enough to survive it. Or Rather, If an adventuring campaign goes on long enough Their stories are going to be a bit over the top. While Good for spreading D&D, it has issues when your party is able to convince people that they're telling the truth, especially if this sort of thing is easily demonstrable. In the Above case, Ghuivere DurFisher, a master spy at Grand Tortuga, was left helpless with a feeling of insignificance. Eof Kveter was incredulous, Luciaria avisen impressed, Slovenka smug and smiling, and Shami Murtuck eager to make a deal. With the exception of that last one, those things don't tend to happen. Be aware of this effect when you run campaign sections that are high in roleplay. 

Lies, But With Evidence

I quite enjoyed the Catharsis I watched my players go through when they landed in Grand Tortuga. Their long and bizzare adventure was a campaign of two and a half years to that point, both in game and out, and it would continue for another half a year out of game and another month in. Suddenly, after months of desolate coast and hostile towns, they came to a place where every person they would meet was at least Level 10. A brawl in a street became a massive cluster of teleporting rogues or Illusion-aided mobsters. I had made sure (or so I thought) that my players were out matched. 

And then a Mouse Roared

More specifically, they managed to get out of a Colville screw thanks to their druid picking up some magic that aided their escape. A unicorn Teleport and a risky alliance later and all of a sudden, they're sitting on a council of Fourteen other pirate captains giving what was more or less the monologue above. Sure you can have people say "I don't believe you" but when your figurehead is the body of one of that sandstone god's own minions, your boat is covered in the colors of Dragonscale that you mentioned, and the people at the table are entirely aware of the extremely nearby Slaadi presence. There's not much that they can say to really express skepticism. The fact that you as a DM have to make their journey interesting vastly conflicts with the ideosphere of  a world of people who tend to get up in the morning, work to fund their next few meals, and then have a pint at the local pub.

True purpose, Right Action

So what do you do, when you players walk into the courts of kings, demanding audience, wielding apolitical power, telling the stories that no one should believe but having proof that no one can deny?

Honestly, I just say that you let them.

This is one of the reasons I make sure that the Density of the towns in my world are high while the spaces in between them are vast. That adventure is out there for them to embark upon. They're probably not the only adventurers to have done these sorts of things, but for those uninundated with endless tales of the number of dragons the local caravan driver has had to kill, or for those markets unsaturated by the seemingly mindboggling amounts of treasure from the surely worrying number of fallen civilizations, these stories are a great feeling for your players. They're having fun. Let them. That's the point.

Tonal Dissonance

The inevitable problem is Tonal Dissonance. Trying to create drama when your characters can clearly handle what has been thrown at them is a seemingly daunting task. Trying to establish a serious threat when "Aggressive Sandstone God" is mentioned in the first person and with past tense. What an average avatar of setting might struggle with thereafter might be a false equivalence. Just because nothing is scary doesn't mean that nothing matters. In the above example, the module that followed was one of the best experiences my players had ever had in a similar game. Things that seemed trivial were dramatic, things that should have been scary were epic, things that were supposed to be intriguing were overlooked in favor of more appealing endeavours. Like becoming the ruling party. 

When your Vidience, your audience, your Olfactorience, your proprioence, makes it to this part, they finally have proven they have the agency to accomplish their goals. This is a fantastic turning point. Your players have decided that they can decide. They're big kids now. Finding and hunting down your father's killer? A scry, a teleport, a quick bonk on the head, a couple of well placed fireballs, problem solved 60% of the time. Wanna Restore your temple to it's former glory? You have the funds to build Your god's version of the Vatican. Do you want to become the hero of your village? Shit man, your old village hero was famous for killing two owlbears. Wanna open an interstellar trading company? Go buy the big freighter.

You did it, Character. You succeeded at winning the mission. But what this means for the future is that there are few people who are able to deal with these problems and as mobile as your rag-tag band.

As the Master of this Ceremony this allows you to open up the shape of challenges. Time becomes a threat, you can place literally any challenge anywhere. You're reaching the end of your story in a natural way.  Instead of  Tonal Dissonance, you have feelings of empowerment and agency, and it is at this point that you know your group is in your game. Anything that they choose to tackle will feel good, feel real. Their deaths, should they occur, will feel justified. The hole left by a character leaving will be aching to be filled, and the journey to find their new partner can be quite a fun adventure. Where are they? Some dungeon, rotting away? In an old inn on the edge of the country? Actively assassinating a political leader? Who knows?

The tibeaux effect in the end is a sign that your characters are ready to take the adventure into their own hands, or at least that it's time to up the potency of your villains. The average joe can't even begin to affect your actors, so now, only the big players can. Kings, Archmages, Lich-Bard Princesses that pine away in the skeleton of their empty society, unable to join her people's children, two thousand years removed for fear of the demon they actively paint her as, Their favourite barkeep, Merchants, that sort of person.

Rau Ranoru'u
-Nirrum