as saionji says, all the people of ohtori are trapped in their coffins, held hostage by their memories. utena’s memory of the prince. saionji’s memory of a better time with touga. miki with his sunlit garden, juri with her locket, nanami with her memories of touga, touga in his ideal of princehood. only anthy is not held by a memory, but instead by a very hostile present. the million swords impaling her.
they want a return to their idealized states. akio promises this to them. he promises adulthood, a revolutionary world where they can be loved unconditionally, freedom from the powerlessness of childhood. he shows them the end of the world and the path they must take to revolutionize it. he promises a fast red car, a rose bride, a castle in the sky. princehood. eternity.
to anthy he promises nothing. to anthy he gives her nothing. all he tells her is that only he could love her, forever, and that witchhood is all that is left to her now. he promises her an eternity of cruelty. she accepts because she does not see another option.
as akio and anthy know, the idealized memories of the duelist aren’t real. the sunlit gardens of their memories were far messier than the reality. there’s no returning to the past, no matter how much power one has. dios is dead and he is not coming back. so what then of akio’s promises of eternity? are they completely fake?
at the end, this is the only eternity he can genuinely offer: an eternity in a coffin. a closed world where you are a living corpse. there is no way out of the coffin with him. only the darkness of a sunlit garden. you will be trapped, just as trapped as you were before you started. it’s why akio talks about the movements of the stars so much. revolution, for stars, is simply a return to the same place that they started.
from the director’s commentary on episode 39:
in the end, the only way anthy is able to escape is by realizing that her past has no power over her anymore. and out there, in a messy future full of light, utena is waiting for her. she can leave akio to rot in his coffin alone.
her coffin is empty. she steps out alone into a world where there is no roads.
