Natsuno was born in the Heian Era and was a talented earth-user in the temple where the other skilled onmyoji trained. She worked alongside Daigo until he was suddenly murdered in the wake of the assassination orders that targeted Mao. Little by little it became apparent that Natsuno was severely ill and was being treated by Masago. After the destruction of the onmyodo temple, the survivors all went their own way. Years later Kamon found Natsuno near death as she wasted away in a temple-run medical enclave.
What happened to her next is a puzzle even to Natsuno. A small earthen golem came to her in the night, offering to heal her on the condition she would make a pact with it. When she agreed the creature manipulated her memories so that she would know what her task was without having to be told. Over the next 900 years Natsuno was to gather scattered body parts. Upon finding the needed parts they would disappear and she would instinctively know what the next part she was to seek would be.
By the 1920s she once again encounters Mao and Kamon, her old comrades. Kamon no longer trusts her, as he witnessed the pact the made with the mysterious earthen golem so many centuries ago. He does not understand how she could have healed and initially suspects that she may have been in league with Shiranui. Eventually however Natsuno is able to prove her loyalty to Mao and those opposing Shiranui and that she has no interest in continuing the centuries long mission to murder Mao. Her only concern remains finding the final body part, a right hand, needed to complete her contract.
The Meaning Behind the Name - 夏野
Natsuno is written with two kanji that mean "summer field".