This is Ayumu, best friend, fellow free-runner/criminal-partner of "Big Bear" Isamu, and most definite love interest of Isamu.

Although Isamu has trouble realizing poor Ayumu's feelings...

Anyways, Ayumu stands at a staggering height of 5 feet, 3 inches tall...so she's really short. Her personality is bubbly and refreshing to anyone (unless you have no soul or a complete jerk) who comes her way. She does not have many fears, but becomes extremely uneasy when in the presence of children due to a horrid accident in the past involving her little cousin.

Despite her happy demeanor, Ayumu has her demons just like any normal individual. I believe her quote in the picture hints to that.

If you can't read the quote, here's what it says: "People make the saddest faces when they die but if they don't see it coming, then their last moment on earth won't be so bad."

Story Origin: "I'm Onee-Chan", K-On Fanfiction