None, Demetrius currently resides within a specialized containment chamber in an undisclosed location in the U.S.A. (though several internet leaks place his cell in Phoenix, Arizona)
To most, simply beyond belief. Demetrius, as a psilor, not only commands a tremendous energy well to draw upon and manipulate at will, but is also able to attain a pure, cohesive energy state (the "true" form of the psilor). While in this energy state, Demetrius is completely impervious to physical damage, and he is able to attack quite freely while in such a form.
Demetrius Yaermon is one of the most effective generals of the Death March, and a major instigator of the great war. Since the beginning of the conflict, Yaermon led his army to complete victory after complete victory, opting to completely and immediately destroy anything he could see that was not of immediate use. He is known for two things: his devastating push during the later years of the Death March that put Europe in danger of invasion, and his stubborn insistence to never give up on the war, which eventually led to his capture. He was apprehended through a huge, complex operation that utilized the finest and most advanced magic and psionics that America had to offer, and still fought a grisly struggle that ended with many soldiers dead, and Demetrius's abilities bound.