Dimitri.

[His voice was sharp, unflinching in the face of imminent violence. Considering it looked like Dimitri could snap him in half like a twig, it was quite the attitude to take.]

Sit down. First of all, if we get this wrong it'll be more than just one head rolling today. Secondly, the mental aptitude to lay a complicated trap is hardly unique to Edelgard or anyone else.