The Azuma Clan is a prominent family of assassins. They are one of two assassination clans that existed in the country since ancient times, the other being the Kuzunoha. The Kuzunoha are the main branch and the Azuma is a branch family. However, interactions between these two clans have almost died out.
They live in the hidden Yama Fukaki 'Village', polishing the skills inherited by their ancestors. They specialize in combat and assassination techniques.
Before Tokaku was born, her grandmother was the head of the clan and had twin daughters: Karami (the oldest) and Mako (the youngest). Karami was supposed to be the successor of the Azuma Clan but due to Tokaku's birth, her mental state was altered and she began to oppose her mother, who chose Tokaku as the successor, resulting in her being rejected. Mako never reached the ability to and resigned from the very volition of being the successor. Karami's dying wish was for Mako to take over.
In present time, because she has no relatives, Tokaku is the sole heiress of the Azuma Clan.