Efficiency and finishing the mission! Barnaby just looks the part way more than Prussia does. To be honest, Barnaby would remind Prussia of his little brother Germany with his stiff demeanor and seeming lack of a sense of humor. The more annoyed he gets, the more Prussia would bug him just because.

Would you mind giving me a bit more about Barnaby's personality/traits. Maybe we can see what else they have in common (the more similarities the better the ritual works after all). And I can double check about the bunny thing, too.