She sounds great, and I really like the npo angle, I had hoped to get Marc into plots like this. And Dee is just wonderful, it's hard not to be enamored there :3
Marc is pretty quiet, diligent, tends to come off as a grump because of his reserved and analytical nature (and because sometimes he kinda is), but overall he's a really sweet guy who's just sort of embittered by life and a divorce that crushed his heart. He's a big nerd with a pretty good sense of humor, an athletic/active disposition and a big lover of animals.