Kei is the tallest in the trio with long orange hair that is almost as long as Nanami Momozono's hair and dirty green eyes.
Amongst the trio, Kei is the most mature but also the most hot-tempered who is intuitive and picked up on the fact Nanami Momozono liked Tomoe. Kei gave advice to Nanami on how she could get his attention.
She is rarely ever seen without her cellphone, on which she constantly sends text messages at a rapid pace; most of the time she does not even bother to glance at the screen. She spends a lot of time dating boys although most of her relationships do not last long.
Ami and Kei were friends even before she met Nanami. She wants to protect Ami due to her naive personality.
She became friends with Nanami through Ami. Since the first time they talked, she immediately noticed Nanami's crush on Tomoe and adviced her to look nice for Tomoe and go out on a date with him.
In a special chapter, it is shown that she will inquire about any improvments between Nanami's relationship with Tomoe. When Nanami said that relationship stayed the same, she advised her to wear fancy lingerie and stated that she needed to be reborn.
- Kei's surname Ueshima means "above, top, upper" (上) (ue) and "island" (島) (shima).