Shinju-kyo
From Inga no Kusari wiki
Shinju-kyo is Morioka Mio's glint.
The Shinju-kyo is a small-ish bronze handmirror, about 15 cm across. The front has a reflective piece of glass in it, as per usual in mirrors, and the back of the mirror has detailed, skillful carving of the eastern Zodiac signs, as well as various mythological figures, gods, goddesses and demons alike, including the goddess Amaterasu. It's the colour of bronze, though it's very faded, matte-surfaced and with subtle hints of green here and there due to oxidation.. The mirror is very slim and light, and surprisingly durable for something made out of glass and bronze, possible hundreds of years ago. The mirror, and whatever mirrors are currently in use, have a glow almost the colour of mint green at the edges of the mirrors.
Glint Ability
Shinju-kyo has two functions. The perhaps more readily used function is communication: if Mio has tagged a mirror with her reiatsu, she can search it and open a communication link, much like a video phonecall. It takes fairly little of reiatsu to do this, and she may also at times use this to open a one-way link through which she can spy. Of course, reiatsu-sensitive people may notice their mirrors suddenly leaking out foreign reiatsu, but other than that it's fairly sneaky.
The other, more drastic use for the mirror is teleportation. While holding Shinju-kyo, Mio can use any reflective surface she can clearly see herself in as a waypoint into a World of Mirrors, and pick another mirror she can emerge from. There are a few conditions more, however. The mirror she enters through and the mirror she exits through must both be large enough for her to physically go through them (a large bathroom mirror, for example, could do in a pinch but full-length mirrors would be more comfortable), and while she has an easier time moving from tagged mirrors to others, she can wing it if needed.
She can also communicate from the World of Mirrors through other mirrors, but the sound of her voice is much more garbled and faint that way, like echoing whispers. Also, one has to actively want to go through the waypoint into the world to enter. If they hesitate, or keep thinking "I don't want to", they will meet solid surface and not pass through. This also means that a person must be conscious to enter, unconscious or sleeping people cannot be pushed inside.
Using the World of Mirrors is dangerous, however. When entering, from anywhere really, you come into a grand white entrance hall with a stairway up and then white corridors upon white corridors of mirrors, with no real logic or stable architechture: even if the corridor seems to go straight, you will always end up back in the entrance hall. Laws of physics and reality seem to lose meaning within the world, and they indeed do. Even time seems to pass oddly, sometimes it will pass as in the real world, sometimes it will pass slow (or fast, depending on how you look at it) so that 15 minutes in the World of Mirrors equals to about 1 minute in realtime. The dimension is saturated with reiatsu, which has caused an atmosphere that, the longer you stay in it, will start to hypnotize a person, slowly but surely.
Disorientation, hallucinations, illusions, the longer you spend time in there the stronger and more realistic they become. And after a while, you forget what you needed to do, forget what you have in the real world, and start to forget that you've ever existed anywhere but in the World of Mirrors. Many who have been able to enter it have eventually become lost in their own fantasies, lured deeper inside the dimension for reasons unknown, never to be heard from again. The stronger a person is mentally, the longer it takes for them to succumb, but given time, everyone will.
While it seems to the person inside the world that the mirrors on the walls seem to start disappearing one by one, and the eerie all-white greenery starts to appear more and more, the mirrors are still on the walls. The mind of the person, however, doesn't want to see them, as they are forgetting the reasons they have to return to the real world and thus have no need for the waypoints. And though one cannot enter the world unless they want to, they can be pulled out of the world against their will.
Using mirrors as transportation is also fairly taxing on the reiatsu reservoirs, and shouldn't be attempted in rapid succession or more than twice a day.
