I have an AU in which Japan is still locked in the Sengoku era. Currently, there are only six known* characters; Koyama Ryuu, Koyama Akemi (mum), Koyama Toshio (dad), Ryuu's two sisters, and Tajiri. While Ryuu lives in a modern Japan-equivalent, she still identifies as more from her home reality and clan then from Japan. What's the proper "nationality" of someone from pre-unification Japan?
* several more presumed from Ryuu's bio
* several more presumed from Ryuu's bio
..."[ S ]he didn’t decide to become a shinobi until she and her father returned from visiting the smith Tajiri to find her mother and sisters dead. A few days later, the Koyamas returned to Tajiri’s forge and commissioned Ryuu’s first pair of sai from her. Thus, they resumed their family’s patronage of the smith’s family"....