My new (and probably incorrect) theory on the meaning of the sun: The Red Sun represents Calliope's life span since the sun is about to die and she is most likely never waking up again and the Green Sun represents uu's/LE's lifespan since it was just created and uu is most likely going to take over their shared body so it is a new life for him and the Green Sun broke LE's seal bringing him back from wherever he was.
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My favorite song as of now: http://soundcloud.com/thelivingtombstone/tombstonediscord
My bunnyslug: http://img.imgcake.com/nio/catapngzu.png