I tend to know more than I'm letting on (and overwhelm anyone who inquires with endless babble and metaphors), quickly jump from one topic to another, and avoid stating my motives unless withholding them proves to be... problematic.
I'd probably be the one patching up the crew, creating new gear, and providing necessary tactical information. Definitely a support unit. Always searching for better solutions.
A fan long range combat, stealth, recon and manipulation. But, well placed explosions are a guilty pleasure of mine.
I'd be that scientist or mage that's always wandering around... doing what he pleases... intruding, exploring, running experiments, messing with people, touching everything.
Like a... Salarian Dr. House.