The Queen Earth royal who sent Kanon to Earth in search of Nurse Angel, Helena also occasionally supports Ririka using telepathy.  In the manga, she is the Nurse Angel of Queen Earth. Because Nurse Angels defend the planet only by their existence in the star system, she cannot support travel to Earth or Queen Earth will fall completely to Dark Joker. The state of Queen Earth is reflected in Helena, and due to Dark Joker's widespread corruption of the planet with the Black Vaccine she is extremely ill.  Although she is holding off Dark Joker's invasion of Queen Earth by her own power, she continues to grow weaker from the effects of the Black Vaccine.  Only finding the Flower of Life can save Princess Helena and Queen Earth.    Source: Based on Wikipedia character description.

The Evil Forces of Dark Joker are closing in on our planet after having destroyed the beautiful planet of Queen Earth. Now, 10 year old Moriya Ririka, with the help of her childhood friend Seiya and the mysterious Kanon, must transform into the Nurse Angel and find the elusive Flower of Life, the only way to defeat the evil forces. The Flower of Life, that once bloomed all over the Earth, is where no one thought it ever would be. And Ririka must make the hardest decision of her life in order to acquire it and rid the universe of evil once and for all.
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(Source: Anime News Network)

Birth name: Tomoko (智子) Yoshikawa (吉川)

Ririka is an average student that can, in fact, transform into "Nurse Angel" by using a special nurse-like hat given to her by her senpai Kanou (who is, in fact, from another dimension/world connected to this one). Ririka's fellow classmate and neighbor is Seiya, who follows her and helps her as much as he can. Aside beating evil monsters.