So called "Death angels" came here from space and can kill anything in matter of second... However they are blind.
You'll have to survive in the world where any sound you create might be your last. No weapon can kill them, no wall will stop them, their only weakness is high frequency sound, use it to defend yourself.
Also, wool makes most sounds undetectable for monsters so you can for example safely place blocks on it.
Videos about it:
Mod is compatible with Voiceless Survivalso if you want Death angels to hear your voice use it It might be bugged right now but it'll be fixed.