When he was first introduced, Rantaro seemed like a mysterious individual. Later it could be seen that he is a carefree and relaxed person, and he is actually described as one of the more ordinary students despite his mysteriousness, with he himself stating that he can sometimes get a bit overwhelmed by the others' stranger personalities. Nevertheless, he is shown to have more patience with some eccentric students like Kokichi and Miu, with a tendency to laugh off some things they say.