I'm getting some Alien Isolation vibes from the gameplay of the new FNAF trailer and I very interested in how this game turns out. Now I want to see Scott Cawthon design an animatronic that looks like it crawled out of H.R. Giger's art and added into the game as a special boss or enemy.
Mythra/Pyra are a special case however, they're regarded as the legendary blade the Aegis, she/they do not turn back into crystals and didn't actually "lose" her memory. And Pyra herself didn't even exist originally, Mythra experienced such a traumatizing experience in her past life that she basically created her other half, Pyra, as a way to cope, and now suppressed all her former memories of it, in part by creating pyra.
EDIT: also in typical weird anime fashion, some blades and drivers do become lovers, though they can't breed cuz basically drivers are actual mortal beings and blades aren't. Thankfully the game doesn't go into much detail over this and just kinda implies it/heavily hints it. It's only been implied that blades with a more humanoid appearance tend to fall in love with their drivers, though cuz this is a crazy anime game, It wouldn't surprise me if some drivers fell in love with some of the weirder looking blades...