There is something about him, King Karl. There seems to be something to exploit; his mannerisms are strangely insecure for a king. It is off, a bit too off.
You would need information about him, something that plays on his weaknesses and insecurities, to make him disgrace himself in front of both you and Artuileno, though how exactly you would go about obtaining that information is a thing you still had to consider.
Obviously, he wouldn't carry around anything incriminating or extortable with him abroad this ship. And besides, ransacking and snooping around in his cabins isn't something you would or could do; your retinue wasn't equipped for such a task either.
As the feast started, which boasted a wide variety of seafood, from salmon to oysters, you realised that perhaps the key to uncovering his vulnerabilities lay in his interactions with others at the event. Observing his behaviour and conversations could provide valuable insight into his character and potential weaknesses.
In his interactions with his servants, he seemed curt and cold; with his sons, he talked in a paternalistic but distant manner. Besides that, you had never seen him smile, and he nearly burst out in anger but thought better of it. He seems to have difficulties actually connecting with people; one of the older men he has with him, meanwhile, whispered in his ear once in a while, though he seemed more interested in the drink than in restraining his king.
As soon as the dinner was over and the gathered guests all began to intermingle, you decided to talk to this old man, who had contented himself with nearly falling asleep in the corner.
<span class="mu-i"> ''Whazzit? Oh, it's one of you boys. Come, come closer. I t-t-told you about it b-b-before. Don't mention your father's height to him; the poor lad hated when his height was brought up.'' </span> The old man chuckled to himself, taking another sip of his drink before continuing to share stories about the king's past. Alcohol, it would seem, is your friend in this matter, for this fossil has remarkably loose lips, though perhaps he mistakes you for one of Karl's sons.
<span class="mu-i"> ''Whatever do you mean?'' </span> you asked.
<span class="mu-i"> ''As you k-k-know, your father was the thirsd son of old King Erik VII, and he was always sensitive about his height. He would get quite upset if anyone mentioned it in his presence. H-h-his brothers, of course, relentlessly bullied him for it. Ahaha, how cruel fate must be: the lords elected Karl at the Althing, and he locked up both of their sons.'' </span>
The old man went on to more obscure things, and though he had, for some reason, started the conversation in Tauten, he now diverged back into Svengalian. Still, neither Karl nor anybody else had really been paying attention to you in the meantime; they seem more interested in Artuileno's mastery of the harp than in your quiet slinking to the background.