Once again and forever thinking about how Chris's final action outside of big climactic group fights is using her special Once-Per-Season transformation and named attack to save lives.
While the series as a whole is pretty light in what I'd consider to be "horror," it does have plenty of dark elements. People die, people get seriously hurt, lots of unhealthy/abusive relationships, a LOT more blood than you'd think, and plenty of good ol' fashioned fighting the darkness within yourself.
There are a few examples of cosmic horror however, starting with the primary antagonist of most of the series, the noise. Yes they are kind of weirdly cute, but they are also horrifying. They turn people to carbon and ash. Get touched and that's basically it. They are controlled by various factions, but at their core there isn't some larger force controlling them. They exist and there really isn't anything anyone can do, even if they understand how to fight them since they're endless. We're pretty sure the original noise are defeated, but no one actually knows for 100% certainty.
Then there's the Nephilhim, endless in it's hunger and keeps coming back with the body horror of Dr. Ver. Ultimately, they aren't truly horrifying, they're still monsters that can be beaten.
XV is a bit different however. Uh, spoilers for XV.
I suspect that At the Mountains of Madness influenced episode 1 a little bit. Investigating Antarctica in search of sarcophagus from a long dead civilization is an eerily similar plot point. The true horror comes from everything else surrounding it. They came across this information from reading the stars. Knowledge like this was not meant for mortal hands. And the mysteries only keep piling up. They also discover an extinct scorpion frozen in the ice, dead fortunately, but more unnerving.
Defeating the sarcophagus isn't necessarily a good thing however. People want to more, they want to delve deeper. They have to understand the corpse in the box and the relic it holds. Perhaps Adam was right in wanting to destroy it. It does kick off the entire plot of XV. And yet it could not be ignored, for it was inevitable. You cannot escape the return of something ancient and incomprehensible as a being written into your very being.
It doesn't stay that way however. Symphogear isn't a show about cosmic horror, it's a show about being loud, bombastic, and hopeful, all of which are incompatible with the flavor of horror. But that's part of why I like Symphogear. Each season feels slightly different, but not disconnected.
I'm not sure if it's just YouTube being super extra shitty in searching stuff lately, but are Symphogear clips being actively pruned there or something cause there's barely any high-viewed clips (or any views actually) of all the hype moments from most seasons...
Apparently Crunchyroll was an ass and dumped like a shitton of spoiler clips of XV after they got the rights to stream it but now all it has is a clip of XV Ep8 and its playlist has 32 hidden videos wtf
Randomly thought about how the first and the final antagonists of the show pulled the same trick and both Genjuro and Hibiki got thrown off by it and were left open for an attack