The thing with finding that monster isn't the fact they found one of those... it is the fact that they found the corpse of one.
Those things are hard to kill even for a D-sword user, and this corpse is butchered the fuck up.
And whatever killed it did kill a monster that is the antithesis of humanity... but that doesn't mean whoever or whatever won't kill them too.
As always, thanks a bunch for starting this series, i know it may be temporary, but even then just being able to read this again is a blessing.