Rantzien I really enjoyed that riddle despite being tough. Keep it up, they're always good fun

As for this one, my first thought is of the Black Mages. Particularly one who has already stopped working and is buried, which would cover the dark, dank and hollow inside parts.

The first sign of danger line makes me think early game, but the saviour line throws me off. Unless it refers to Baku, who rescues Zidane in the past and also comes through the left door. The right would then be the first sign of danger because it triggers the battle with Masked Dragon. Or something, I don't really have a guess.