Tsukushi Kinoyama

Tsukushi Kinoyama is a young woman who first appeared in Episode 7 "Botanical Madness" and made her appearance in Chapter 13. When Kiyomaro was young, he would often go to the Botanical Gardens in order to read. He'd find peace there away from other people and as he grew, she would watch over him to protect him in case anything ever went wrong.

Tsukushi is a young woman who appears to be slightly older than Kiyomaro and is fairly tall, being a little taller than he. She has black eyes and black hair, which is usually tied up in two pigtails and wears a white lab coat over a green shirt and a pair of khaki brown pants.

(Source: Zatch Bell! Wiki)