None, Doppler maintains his residence in the New Japanese Empire
Unknown. Doppler maintains an unusually powerful devil as a bodyguard, such that he rarely has to fight, but his magic abilities are clearly of tremendous ability.
Quite unknown to the Empire that houses him within their borders, Doppler is the deliberate instigator of the Death March, and a master manipulator of all that surrounds him. Powerful, influental, but above all, knowledgeable, Doppler draws up power for himself within the Empire while conducting experiments and research. It's unknown what his ultimate goals are.