The story
From em + -self, or by removing "th" from themself (cf. also 'emself, 'emselves).
Etymology from Wiktionary, CC BY-SA 4.0.
emself
em·selfToday it means: Em, a gender-neutral object of a verb or preposition that also appears as the subject, the reflexive form of em, equivalent to themselves/themself (also used for emphasis). Full definition →