99% sure its hell raiser
Ok so with all the letters we have so far / siera
It could spell raise
And with the 4 audio files bhvr dropped on discord
Run it under a sound spectrum you get this
Together they spell raise helI a quote from HeII raiser
Please try to prove this wrong

Comments
Same but I can't deny what's infront of me
yeah it is. Raise Hell
Pretty much.
This is all just a red herring which clearly makes the killer Red Herring from a Pup Named Scooby Doo.
Raise hell can relate to several horror franchises.
Hellraiser being the most obvious, of course.
Hellraiser is the franchise. Pinhead is likely going to be the killer.
99% theres still the post about the red hering perk