Hes roughly 100 lbs, ~ two years old.

His favorite thing in the world is to walk around with things in his mouth.

Adorable. Big dogs are the best, they are usually cuddly couch potatoes that double as protectors.

I have little experience with Dobermans though, how is his temperament?

His temperament is amazing, other than he gets too excited for his own good.

Doesnt realize how big he is.