Iirc and if im not mistaken AND SPOILERS TOO because this is the big reveal later.
Remember how the regas candidate was so obsessed with the bacon that he keeps asking Garas for it? And how there's this character that's on the side of the Duke (i think its the marquis?) that keeps eating in large amounts during the dining with Karas?
Mataaz is tasked to cook the meals with the salt in that bacon, because that salt makes people addicted to it to the point that they will become crazy and mindless enough to kill people for it. Its effects is similar to how the black potion affects kings.
But if u also remember, Karas did ask the Duke why isn't he eating the meal, and it seems like the Duke is also unaffected by the salt compared to others. U just need to remember this later on too, because a whole history will be revealed why the Duke is the only one unaffected by it.
Oof my bad, i think i remembered wrong about the meal itself... I meant how the people dining especially the marquis who was eating in large amounts...
.
.
.
.
.
.
.
Add too much salt because the food was bland. If in not mistaken, Mataaz was tasked to keep the food bland as shit so the ppl that is siding with the Duke will keep adding the salt, hence, poisoning themselves.

novel readers, I need to know, what has Karas ordered Mataaz to do? will he even live to si Kin? like that's been making me curious, I got to know