Oughhh sandduo.... Wilbur being a prince thats real far down in the line of succession and decides to try and kill his way to the top.
He ends up going to Phil whos probably some captured doctor from somewhere theyve taken over and he asks him for some stuff thatll hurt people.
Mainly so if it ever gets back to him Phil's an easy scapegoat but also because most the conquering happened before he was born so Phil's probably more mad at the others who took active part than him.
Phils originally a bit hesitent but he also wants to kill the people who kinda sorta ruined his entire life so he goes ahead and starts supplying Wil with shit to make people sick.
Wil poisons himself a little as well to try and cover it up more but maybe at one point he takes it a step too far and one of his family members actually dies. While yeah this is kinda what he wanted he is also a young kid (maybe like 15?) so naturally he freaks out.
He ends up going to Phil about it to shout at him but Phil pulls a switcharoo and convinces Wil that he might as well just start outright poisoning the others as well now since that way it can be covered up as an illness / genetic thing.
Wil being a child just fucking accepts this and starts poisoning the rest of his family.
It works but theres like, an entire power vacuum now and he's a child king on running an empire that was already showing signs of crumbling. Revolts break out, famine hits and it all goes to absolute shit.
Wil goes running back to Phil after a failed assassination attempt almost gets him and begs for some kind of solution. This is where I'm thinking Phil maybe reveals that he's been worshipping death (and therefore praying on literally everyones downfall lmao) and offers him a solution.
Its a fast acting, painless poison that'll let Wil take an easy way out rather than facing the mob of commoners that are trying to break into the castle. The guards are wayyy too occupied to deal with Phil murdering the king so its an easy escape for both of them.
Wils backed into a corner so he accepts the offer and drinks it.
What he doesnt know is that Phil and Kristin have both taken a liking to such a bloodthirsty little prince. Its not the first time Phils been captured like this in the thousands of years he's been alive and its certainly not the first poison he's ever made.
I'm thinking he works kinda like a tumour for whatever kingdom hosts him. He's a herald of death so, by the royals trapping him as a show of power, he's slowly poisoned their empire and now its all crumbling again.
But he likes Wil because Wils a crafty little guy and he gives him a poison that'll just make him look dead and bind him to Kristin in case he ever tries to get away.
He, like all the other times, just packs his bag - this time taking a passed out prince with him to raise into yet another herald. Maybe this time relating to poisons or disease, since the boy seemed so fond of it.