She's either an invader herself, or one of them crazy invader rights activists, or an invader accidentally saved her life or something.
EDIT: I was completely wrong 🤣
D want to kill all of them anyway so the order doesn't really matter.
Him being a meticulous information broker makes him one of the most dangerous and the best to take out first (Blue was the easiest to take out first since he was the straightforward type).
She's been trying rizz up D since she met him. Next thing you know she'll orchestrate a wedding ceremony between them in order to lure out a dragon keeper or somrthing.