riku kaitani

 Sena's childhood friend. An extremely fast boy who happens to be the one who taught Sena how to run. When Riku was in elementary school, he saw Sena being bullied and he used his speed to save him. Riku told Sena that he shouldn't have to deal with the bullies and he should stand up to them. Sena pointed out that unlike Riku he had never fought before and he was weak so Riku told Sena he was going to teach him speed as a way to fight the bullies because with speed you have an advantage in avoiding attacks. So Riku taught Sena how to run as a way of building up his speed. After days of practicing Sena finally learned how to dash and run fast. Sadly, Sena used his speed to be a gopher, (though it's ironic that being a gopher is what helped build up his speed). Riku soon left Sena's school because his family needed to move. In the anime, he and Sena made two promises. One was that Sena would always run. The second was that Sena would protect Mamori