Diamond Daydreams (Diamond Dust Drops) (Kita E): Nurse Yuki.

Yuki is a young nurse working at the hospital where Karin is staying.  She was secretly sending encouraging messages to her  patient under the name 'Your Fan' leading to a misunderstanding.  She had been dating Dr. Amakasu since high school.

Bonus: Unnamed characters 

Code E and Mission E: Keiko Komatsuna

Keiko is Chinami's best friend and sits in front of her at school. In Mission E she is now the school nurse.  She can seem flighty at times; however, she is also very observant and seems to figured out the existence of 'OZ' and Chinami and Maori's identity.