Kaoru is the fourth Gatekeeper found in Japan.
She is outgoing and she used to have a scholarship because of her track and field, she also used to have a dream but they disappeared when her Gate Power was awakened.
She was hesitant to join the team and didn't want to help.
But in the outcome she did. Kaoru even liked Shun and actually declared her love (which disappointed Ruriko).
The gate power she possessed was awakened during a race when she got a bit angry that people was talking about her getting a scholarship because of running.
Her gate allows her to run swiftly and display super human strength.
Her attacks are "Kaoru punch", "Kaoru throw" and "Kaoru kick" (She just happened to name them after herself.)