He is shown himself as a stoic, cold and distant person, at times sarcastic and irreverent but also quite cunning and audacious. He is also quite rude.

I have short black hair, grey eyes and I'm 1,60 m tall. Have 30 years old. Captain of Survey Corps. Serious. Cold. Obsessive with cleanliness. 

No one should trust that the people they are with today are likely to be gone tomorrow.

I'll do whatever it takes to save humanity

I don't know anything for sure. It has always been like this. As much as I trust my strength and the decision of my teammates... Nobody knows the result. So what we have left is to make a decision that we will not regret.