Dru doesn't handle problems well, and no matter what he says he'd always rather handle things with a few well aimed shots to the head. Violence is ingrained into him, it was an expected part of life and as a man of the Military Guild something that could be gotten away with outside the normal channels of law.
Emotions are for the Art Guild unless they seem to be anger or indifference. He's become apt at hiding the rest unless you can coax it out of him, which becomes a feat in itself. He's prone to extremes on either side of the spectrum of emotional range.
It's not an unknown concept, and it comes in different shades. He has felt love to his culture, his career and aspects of his family. On a deeper note his Second and his Scientist have spots in those shades.