The Desolation of Smaug has allowed us to understand more deeply the members of Thorin Oakenshield’s Company. Knowing that the audience would not be so amused watching a two and a half hour movie with 12 dwarves looking like Gimli, Peter Jackson saw to it that every dwarf had their own personal history. Evidence of their back stories can be seen throughout the two films, The Hobbit: An Unexpected Journey and The Hobbit: The Desolation of Smaug, if you look closely enough.
Since viewing DOS, I loved discovering that Oin represented the apothecary in Thorin’s Company, and I particularly enjoyed the scene where he wants to stay with Kili in Lake-town because he believes it’s his duty to remain with sick and injured.
Thus, immediately after seeing the film, I ventured to express my personal enthusiasm for this character and I was lucky enough to receive a response from Oin, I mean John Callen, on Facebook:
It seems that we’ll discover even more things about the members of Thorin’s Company in the next extended edition!
It was decided that while Oin was a warrior, he was less that now than a thinking person. He might be an apothecary, which I thought was great. Could I carry with me a bag in which I would keep little samples of things, bottles of potions of various kinds? If anyone was injured or sick Oin would be called upon. It would make sense to have someone like that on a quest of this sort where misadventure was a near certainty.
John Callen, The Hobbit Chronicles: Creatures and Characters