"Black God's Kiss" by C. L. Moore

First appeared in Weird Tales.  Reprinted (in a few genre retrospectives) by L. Sprague de Camp, Robert Silverberg, Martin H. Greenberg, Jessica Yates, Jacob Weisman, David G. Hartwell.

Summary:

Jirel of Joiry, their commander, is brought before Guillaume the conqueror, struggling so fiercely that her captors struggle to hold her despite her ropes.  They remove the commander's mask:  He's a she!

Guillaume forces a kiss on her (presumably of the title).  She bites his neck, and he backhands her.  She awakes in a cell and shrieks.  The guard investigates, and she escapes.

She finds Father Gervase.  She wants a weapon to destroy Guillaume with a weapon from hell.  She descends a circular tunnel.

She encounters a mirror self that tells her to enter, but she refuses.  The mirror self laughs when she seeks a weapon to kill Guillaume. She fights her way out but knows that she must strike or it will strike her.

*Spoiler*

She kills Guillaume with a kiss and immediately regrets it.

Commentary:

This is a surprising one.  The man painted as evil becomes the man of love.  While perhaps intimated somewhat through both of their loves of violence, through the kiss, as a guy it's hard to buy.  On the other hand, there's a long literary history of quarreling lovers--Gone with the Wind, most famously--but usually the two exchange more attempts at love?  Or maybe that's the problem, that she didn't recognize love until it was too late--and the mirror-self knew this unconsciously through the laughter.

"Jirel was... equal in battle to any swashbuckling male hero.... Every male reader loved the story.... [T]he first one remained marginally the best and most original."

--Lester Del Rey,  The Best of C.L. Moore

"If you have read past Shambleau to Jirel, you will probably have noticed what a close relationship the two women bear to one another.... [B]oth were versions of the self I'd like to have been."

--C.L. Moore,  The Best of C.L. Moore

"[H]er work has a texture and emotional intensity[,....] lyrical fluency and the power to evoke a Sense of Wonder in the past-haunted interstellar venues that were her specialty."

--Science Fiction Encyclopedia on C. L. Moore in general.

C. L. Moore on how she constructed stories