Though not much is known about Miyuki she tends to disappear for long periods of time and then reappear somehow having gained a significant boost in her life expectancy, most likely due to either trips to the outside world or uses an immortal time travel as a tool to explore+
The multiverse for new prey, as a very special fox youkai she needs to drain the life force of other living beings to survive she does so through her concerts which allows her to mass drain from all those who attend she has been known to leave her victims alive too
When she does travel to different universes she tends to take on a new identity as there are other people like her out there who hop universes, though she has formed a bond with a certain hellcat in her home universe whom she finds a comfort in being with.
Wait…why is there so much redacted info on this page of her file…strange…I’ll put in my clearance code and done now i can see- [an audible gasp from a female could be heard these were obviously recordings from someone…] S-She c-could cause a end of the universe senario…fuck
I have to warn my superiors! [the recording would end with a click…]