So, the first tankoobon volume has just come out in my native language (Brazilian Portuguese) and there is a small clarification in Oga's profile.
Remember that small dragon drawn by the author next to Oga's picture? That is supposed to be a mixture of a Dragon, a Deer and a Snake (the other characters in Oga's name).
One of the most underrated protagonists. He is loyal and dedicated to his friends and most importantly, Beel. Even though he was reluctant and pretends he wants to get rid of Beel, we know how deep their bond is and how strong their love is. He also had a great design and is wicked strong.