Trivia: Military combat training (both arms and close quarters), military education after serving from age 15 on and being shot during a mission, almost lethal.
wears AR-cornea-implants and glasses to enhance the effect
Grows and tends to his hair as an old act of rejecting war service

Edren is mostly easy to look at, but not exactly easy to handle.
At first he's rather agressive, dominant and a drive hard to ignore; snappy, if one gets in his way. He's a workaholic, due to personal  reasons, and it's showing that he's walking on a thin edge. His build and behavior don't suggest that he's actually quite open to emotions and able to forgive himself weakness, but he doesn't take shit from anyone trying to get on his scientific nerves.
Growing up in a middle-class household that went downhill, he has a fair share of family issues, but whomever he considers family will be protected at almost all cost.
As a biotechnic sciences major sometimes he's prone to overanalyse things and situations, and other times he just snaps - which could become dangerous, given that he's been serving the military.
Although most of his stubborn research is dedicated to the government, Edren has very personal reasons to pour all he has into the solution of a seemingly simple problem.

And the one who takes literally 'none of his shit' pulls him out of his tube-visioned marathon and shows him that he's able and allowed to take breaks again, to take care of himself.
Edren learns, that time spent together, working or not, is something he should cherish.
If he's not holed up working or working out , he thoroughly enjoys the simpler things - good food, music, a good fuck and stargazing, for example. Even more so in company.
Or he uses and takes care of his small collection of devices from the early 21st century.