Ren Otonashi (音無 蓮? Otonashi Ren) is the third/youngest sister of the Otonashi sisters and seems to be the one with the most common sense, but has a habit of only seeing the negative side in things and rarely sees the positive. She is also a siren.
- Ren appears exclusively in Rosario + Vampire Capu2: The Rhapsody of Love and Dreams and is a part of a group of Sirens who are attempting to gain the affection of all the boys in school by using their abilities.
- Despite having the same last name, Ren is not related to San Otonashi.
- She is a sister to Rin Otonashi and Ran Otonashi.