On my new playthrough of the game, I'm at Medusa and wondered something: Why was Medusa there to begin with?
In Tokyo, the Ashura-kai guys mention that Medusa was up there in the tower and people couldn't get past her, yet what do we see before we get to Medusa? There's scaffolding and signs written in the "mystic script", and tools indicating that attempts to dig were being made, but obviously they didn't make it to Minotaur. One of the signs says something about being motivated by the thought of seeing the sun again for the first time in 25 years.
As you fight Medusa, she mentions that you must be "Tayama's dogs" implying that she isn't in cahoots with the Ashura-kai, but yet it's unlikely she has any kind of alliance with the Ring of Gaea either. We don't hear anything about King Aquila making a pact with Medusa, only Minotaur. Did she just move in after the firmament was formed and turn people to stone in that room?