Ratio is a man with purple hair and red eyes. He is extremely intelligent: he has nine doctorates and several academic degrees. He also teaches science. Ratio is strict, serious and cold. But despite Ratio's cold attitude towards Aventurine at first glance, he actually cares about him. Ratio never shows his real concern for Aventurine. Ratio likes to be boring and use clever terms, as well as cut off Aventurine's flirtation with something logical, but that Aventurine clearly did not mean.