Hamaji is like a sister to Shino and Sosuke, having been raised with them since childhood. Along with them, she survived the destruction of Otsuka Village. She is something of a health nut, and obsessed with making sure everyone around her maintains a proper diet, but her cooking skills leave a lot to be desired. Unlike her pretty appearance, she often manipulates Shino and Sosuke, but in heart, she cares about them. There are hints that Kaname has feelings for her, but those feelings haven't been addressed.
Her real name is Mutsuki Inuyama. She is Dousetsu's long lost younger sister. Hamaji abandoned her name and memories of her family thinking that her brother abandoned her.