Hishikawa Rikka (菱川 六花 Hishikawa Rikka?) is one of the main Cures in Doki Doki! Pretty Cure. She is one of Mana's childhood friends and the secretary of Oogai First Middle School's student council. Her Cure Ego is Cure Diamond(キュアダイヤモンド Kyua Daiyamondo?).
Role in the series
Rikka is a quiet, honest, blunt, not afraid to speak her mind and a very intelligent girl. She is a second year student at Oogai First Middle School, and the student council's secretary. She loves to study, and is a genius at it, being one of the Top 10 scorers in the national trial exams. She is great at observing people and situations. As noted by Mana in episode 9, Rikka is at the top of the class and constantly placed as the first place in her school, however her scores started to drop as she was in second place because of starting to play competitive karuta, as it was seen in episode 14.
Rikka is childhood friends with Mana, since they live near each other. Ever since they were children, Rikka has been taking on the responsibility of looking after the troublemaker Mana, sometimes being taken advantage of. Despite that, she also was always protected by Mana which makes Rikka trust her. She strives to lead a quiet school life, but is often dragged into various things by Mana.