So I gave the characters a chance to go dark. One of the poets mistakenly wrote about how the heroes perished in their greatest battle ever. They enjoyed hearing about it, and added some details about the heroic deaths of, uh, their teachers and icons.
Besides, there were more troubles brewing in Japan...
"What kind of troubles?"
"Coronavirus... I mean, uh, plague. An eeevil plague!"
A plague spread by a cult, which is something that the characters decided to investigate, since it was rumoured that the cult has a base of sorts somewhere in the wilderness of Geishu province, and one of the characters was good in Tracking. On their way, the party discussed if the whole plague thing was started by one of the characters who dabbles in necromancy ("I didn't do it!" "Maybe it was your evil twin". "I don't have an evil twin!" "You said you don't remember your family". "Well... I think I don't have an evil twin...").
Which led them to a pyramid surrounded by hundreds of half-mad cultists, with Dance Macabre Skeleton Musicians playing their horrible music on one of the levels (apparently this is Zak's version of bards being cool), and the Plague Standup Comedian dancing and giggling on the top.
The characters then proceeded to make reasonable decisions. They chose not to fight with the cultists, because the cultists didn't get in their way and let them come closer to the pyramid (since the cultists are merely mind-controlled victims, killing them is easy but leads to loss of XP). They also chose not to fight with the Skeleton Musicians, because guys are just jamming a session and having a really good time.
At the top of the pyramid, there's this comedian skeleton who yells magical jokes at people. And also the doubles of all the characters.
"Oh my god, it's true! It is your evil twin! And your evil twin! And your evil twin!"
"And your evil twin!"
"My evil twin? That's ridiculous!"
So, the party decides to fight their evil twins but very soon recognizes that the doubles don't really do anything, so they leave the doubles alone (if a double is hurt, the damage is magically transferred to the person that the double is imitating).
So they fought the skeleton jokester.
Now, his magical jokes work like this - if the victim of the joke fails the save, they are pushed back and take damage. But if they immediately reply with a better joke that makes someone at the real table laugh, the skeleton's joke fizzles. The players didn't know that but they figured it out.
After having two of his jokes blocked like that, the skeleton got rather upset.
"He looks at you, and yells: "Your mama is so... oh, forget it!" He just swings his stick at you!"
By the end of the fight, the NPC bard was thrown off the pyramid by the magic of the joke - then the fox samurai jumped off the pyramid to save the bard from the necrolarvae - then the pig monk grabbed the skeleton jokester and jumped off the pyramid to crash the jokester against the lower platform. Then the cat courier shrugged and jumped down, just because she had the best acrobatics and landed perfectly on her feet.
And this, my friends, is how coronavirus was defeated in medieval anthropomorphic-animal-inhabited Japan.