Talk to Muzet in the Reize Harbor side of Marksburg to catch up with Nigel and Muzet will want everyone to gather around for something.
I have a feeling that Muzet’s reputable source has something to do with whatever Nigel was preparing. Oh well, choose who you want to join Ludger, Gaius and Muzet and then make your way to Elym Harbor to find the monster in question.
This battle is only difficult if you do not prepare accordingly by using a Muddle Ward on your main healer to prevent Confusion. With no weakness you can use any weapon you like, but you’ll want to focus on attacks that hit the critical point on the Gentleman’s head, such as Crimson Fury or Swallow Flight. It is possible to get the Gentleman in a power combo, but with a high iron stance combos tend to be short lived.
The main attack you want to watch out for is Battle Beam, which shoots a beam of damage straight ahead that causes many ailments including confusion to everyone. depending on who is in your party this can be handled by either using Dispel or simply waiting for it to wear off on most of your party… as long as you survive. This attack is why having a Muddle Ward on your healer(s) is vital, especially since this boss spams this skill at low health. The rest of the Gentleman’s attacks can hurt, but shouldn’t be too much for your party to handle.
After the fight the group figures out what happened, but the outcome wasn’t exactly what Muzet wanted. Although Muzet’s actions were pretty crazy, it’s sort of to be expected from her… right?