The name Promare sounds familiar and the beings are associated with fire. They're probably a nod towards Prometheus, the god who gifted man with fire.
Then wouldn't that make Kray and his dragon, Biar, Kratos and Bia, the two titans that chained Prometheus?
When looking back on the news reel at the beginning of the movie, all of those clips paint Burnish in a negative light. During this time, Kray became the governor, and therefore has a lot of influence over the news, which is later emphasized by his voice stating how they need to do everything they can to stop all Burnish terrorists.
A reason that Thyma couldn't be revived by Lio but Galo was able to revive him? Galo was healing Lio with his own flames, whereas Thyma's flames were already running low and Lio's weren't able to reignite it.
It's pretty clear the Burnish's flames don't behave or look like real flames, but knowing Trigger the audience will chalk it up to Rule of Cool. But then we find out they aren't actual flames, they're the Promare, so the twist was hiding in plain sight.
The battle theme song "Kakusei" has lyrics that sound like gibberish. However, if the song is being sung in the perspective of the Promare and Burnish, the gibberish might be the Promare's alien language.
Lio's theme "Λsʜᴇs" playing when Galo wakes up after being captured and see several Burnish hiding in a cave with Lio has a Brilliance in its lyric "Uncertain flame of hope I found, Will you lead me back on the right track?" To quote one YouTube comment:
This plays when it zooms in on GALO and when he tries to offer Lio help to save a fellow Burnish from death. Coincidence? I THINK NOT! Since Ashes is Lio's theme and thus from his POV, you can DEFINITELY say that Galo is Lio's "uncertain flame of hope" given that "burning firefighter's soul" of his that makes him want to help and save people, INCLUDING THE BURNISH. For so long, Lio and his people have probably never met a non-Burnish who has wanted to understand and help them. All they ever faced was fear and hatred from Galo's people, so to finally meet someone selfless and non-judgmental like GALO makes Lio believe that he is the "flame of hope" who will lead him and his people to a better future.
When Galo walks up to Kray despite Kray using his full power in the climax, it mirrors their first meeting. Kray's rise to fame started when Galo was running away from a flame source he started (albeit by accident) towards him, his downfall would start when Galo started walking towards the flame source which he started.
Fridge Horror
It's stated later in the film that the more pain the Burnish are, the Earth gets closer to having its magma at the core burst open due to the Promare at the center. Throughout the movie we see many Burnish captured and experimented on, causing who knows how much physical, mental, and emotional pain. In other words, the rush to capture Burnish and finish the pods are causing the magma to burst faster.
Why do so many captured Burnish have bandages? Because there were probably experiments to test their regeneration abilities.
While it was a good move on Heris' part, how many Burnish people ended up dying when she over-fueled the engine so it would cause the ship to crash?
When all the captured Burnish use their flames to help Lio it looks like they're all accounted for. Now as for the people on the Parnassus...
" playing when Galo wakes up after being captured and see several Burnish hiding in a cave with Lio has a Brilliance in its lyric "Uncertain flame of hope I found, Will you lead me back on the right track?" To quote one YouTube comment