[ he's explained it a few times but he knows it so instinctively that it's not necessarily a chore to explain it again, even if it's been strange to be the educator on this.

looking at her for a second, he pushes himself off the wall, stepping over to her side of the room. sitting on the edge of the bed (hopefully kirigan doesn't mind his sheet-covered ass on it), he angles his back to her so he can point to his neck, where a scarred line runs horizonally on the nape. ]

Right here, there's a disk that's stored in every person at the age of one. It stores DHF — basically human consciousness which can then be transferred to bodies anywhere, any city, any planet, in seconds. The body dies but as long as the data's intact, people can keep living.