Gender neutral reflexive pronoun — equivalent to "himself" and "herself"

How would you refer to a gender neutral subject with a reflexive pronoun?

It is unbelievable how a perpetrator will cast oneself in the role of victim.

That does not seem right. Is there a better word other than "oneself"? I thought "oneself" would refer to the narrator. Here I try to refer to the subject.

Themselves: It is possible to use a 'singular they' for pronouns, but to say "themselves" surely can not be correct as a gender neutral reflexive pronoun? According to this article, it would only seem to make sense when qualified by a singular they.

Themself: "The form is not widely accepted in standard English" according to the Oxford dictionary.

It is unbelievable how they, as a perpetrator, will cast themselves in the role of victim.

I'd like to avoid making the sentence this complex.

Answer

This is just another version of the he/she, him/her dilemma: English lacks singular pronouns that include both genders. I like @drm65's approach to avoiding the problem. The other likely option is to specify both:

"himself or herself"

It is unbelievable how a perpetrator will cast himself or herself in the role of victim.

Or:

"him or herself"

It is unbelievable how a perpetrator will cast him or herself in the role of victim.

Update:

Another approach is to just choose a verb that isn't reflexive:

It is unbelievable how a perpetrator will play the role of victim.

That's not always possible or best, e.g. when you're trying to emphasize exactly that reflexive aspect of the issue. But play is obviously shorter and simpler than cast him or herself in the role of, so it's worth considering unless there's a good reason to use the wordier version.