WMG: Johannes Cabal the Detective
Cabal will eventually succeed in resurrecting the mysterious girl but with disastrous consequences
She will return to life but not as the person she once was but as some corrupt Death Goddess
who will be hell bent on ending the world forcing Cabal to put her down with the help of Leonie Barrow and (hopefully Horst, if he ever magically comes back from the dead, too
It would be hard to believe that Horst is actually dead
given what happens at the end of The Fear Institute.