Prusena can be seen by anyone, but without the light of the sun, she can't produce rainbows.The living can't get in or out……If that's really the case, then what we see over there must only be Prusena's spirit,
and she must still be bodily present on this side, just invisible… I guess.Right, so maybe she's fallen in here…Prusena hasn't got any heft to her, so that's not a problem.She has something in common with Merudina and Nayukis.