Vetis

Though most of the Medical Department staff have an infamous reputation, even they somewhat fear Vetis thanks to his sheer insidiousness.
A toxicologist by trade, Vetis works tirelessly to make the most potent and painful poisons he possibly can--some of his creations are strong enough to kill even the biggest, toughest dragons a thousand times over. Vetis treats each of his concoctions like a work of art, even going so far to show off his favorites on custom display stands in his private quarters. His descriptions of the ingredients and effects of each poison read the way an experienced wine taster might give a vivid description of their drink's flavors.
While Vetis's obsession with his poisons might come off as alarming to some, it's not what makes him so abhorred; rather, it's the way he tests them out.
Vetis believes that his concoctions deserve nothing but the best and most accurate methods of testing their quality: usage on live subjects, especially other dragons. Of course, nobody would willingly drink something they know to be poison, so Vetis must be discreet; he's learned how to carefully slip doses of his poisons into the drinks of others without them ever noticing... until it's too late.
Vetis has killed dozens of other members of the Compound over the years, and he likely would've killed far more had the Board not finally stepped in. After investigating the higher-than-usual number of deaths in the Compound, they followed the trail back to Vetis, and threatened him with exile if he chose to continue; knowing that he would face far worse punishments for his actions outside of the Compound, he agreed.
From that point on, Vetis has instead been giving his colleagues amounts of poison just barely less than the calculated fatal dosage; and while his unwitting subjects get dangerously close to dying, the Board considers Vetis's actions to be completely acceptable... much to the chagrin of everyone else.
Thanks to Vetis, the entirety of the Compound is extremely paranoid when it comes to drinks; whenever Vetis even briefly passes through a room with any drinks in it, it's become traditional to pour them all out and meticulously wash their containers, even if somebody had been holding or drinking from one of them.