Originally a member of Dark Joker, after repeated failures to defeat Nurse Angel Buros gives Dewey a &quot;body that feels no pain&quot;, leading to his utter defeat and near death.  Ririka saves Dewey using the Green Vaccine instead of letting him die.  Dewey later repays this debt to Ririka by retrieving some of the Black Vaccine and telling her that Nurse Angel has the ability to transform the Black Vaccine into Green Vaccine, thus replenishing Ririka's supply of the Green Vaccine.  Dewey gradually grows to accept the kindness of Ririka and Seiya, and becomes a valuable ally in the fight against Dark Joker.

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)

Her true name is Fuchizaki Yuriko (渕崎有里子). She works for Sigma Seven. Yuriko Fuchizaki's career is long in comparison to other seiyū of her generation - she began at the age of 10, dubbing films into Japanese for the talent agency Group Midori. Her anime debut came in 1984 with the role of Kishin Shinokawa in Persia, the Magic Fairy when she was in 10th grade.    She is the middle child of three. She was married in 2005 and is the mother of twin sons.

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.