Dr. Sakuma is the adult of the game, and acts as the parent for the kids who join, and the leader for everyone else, despite giving many decisions to the mature and insightful Yamato. He is the game's unofficial narrator, and most scenes are told from his point of view, if not from Yamato's or Jegard's.
He worked for and apprenticed under Dr. Gidoh for years, beside Dr. Misaki, as a scientist who worked with bugs and similar creatures. His nephew is Tsubasa, and her friends come and visit him, as they like bugs too.
He doesn't have much characterization, like Tsubasa, and is just a simple working-class adult who is protective of his nephew and his friends and has a love of his work and bugs.
His drone is Dor-O, a snail drone. The snail is the only drone who does not level up through battle and cannot equip any equipment besides what it automatically has. It's weapon, however, increases in power when it reaches certain levels through base fortification. Doro is a japanese sound effect for slow, often lazy or silly. Ironically or not, verbalized sound effects are much more frequent in entertainment for children or families, and Dr. Sakuma takes care of the kids in the game.