Such sentence for instance:
Who knows what creatures are these?.
Text editors correct this as
Who knows what creatures these are?.
Which is right or both?
The latter is more normal.
These is the subject (not what creatures - that is the complement).
In a direct question we invert the subject and verb (or auxiliary - irrelevant here):
What creatures are these?
In an indirect (or embedded) question, we do not invert, so the subject precedes the verb:
Who knows what creatures these are?