Pluto's lonely existence - the senshi, not the planet - was something Mercury had understood. (The truth she didn't acknowledge was that Pluto's loneliness was far deeper, alone and unable to leave the Time-Space Door since so many aeons ago.) It was small wonder the planet was cold and distant like its guardian.

Of course, its distance from the sun made that inevitable anyway.

"The heat and cold of Mercury would burn and freeze a human in no time at all," she points out. It's not hard to see her own extremes in that scientific soundbite. Of course, he's not a human any more than she is fully human.

"On that other planet Mercury, did you ever see the kingdom when it was still alive?"