Rantaro seems like a mysterious individual. He is a carefree and relaxed person, and he is actually described as one of the more ordinary students despite his mysteriousness. Nevertheless, he is shown to have more patience than others with some eccentric students, having a tendency to just laugh off some of the potentially hurtful things they say. Even though Rantaro cannot remember his talent, he doesn't seem worried about it, instead, he simply says he just looks forward to finding out what it is. He gives off a really calm and composed vibe, making him seem like a pretty reliable person. His speech is characterized by being very friendly and colloquial.

Here are some voice examples: https://youtu.be/8Nfh9beKX6k