Black Priestess of Varda

She was well-named—Sin, foul witch and raving beauty, Beloved of Sasso, the Dark Power striving to capture, with her help, a lovely little world. Their only fear was a whispered legend—Elvedon, the Savior.... But this crippled idiot blundering through a shower of sparks into their time and space— he could not be Elvedon!
The pen moved clumsily in Eldon Carmichael's right hand. He had been left-handed, and the note itself was not easy to write.
Dear Margaret , he scratched. I understand ...
When after a while the proper words still would not come he crossed the shadowed laboratory and took another long swig from the flat bottle in his topcoat pocket. He understood—he remembered his first one-eyed look in a mirror after the bandages were removed—but still he felt resentful and deeply sorry for himself.
He went back and tried to continue the letter but his thoughts veered erratically. The injury had been psychological as well as physical, involving loss of ability to face up to unpleasant facts, but still he could not force aside those memories.
There had been only a glimpse as the wrench slipped from Victor Schenley's hand and fell between the sprocket and drive chain of the big new compressor in the Institute's basement. He wondered. That look on Schenley's darkly saturnine face could have been merely imagination. Or horror. But there was something about the man.... Still Eldon discounted his suspicions as the unworthy inventions of a disturbed mind.
Only the quick reflexes that had once made him a better than average halfback had saved him from instant death as the jagged end of the heavy sprocket chain lashed out with the speed of an enraged cobra. And often during the pain-wracked weeks that followed he had almost wished he had been a little slower.
The ring sparkled tauntingly under his desk lamp. Margaret had returned it by mail, and though the wording of her note had been restrained its tone had been final.
He picked up the pen again and moved the stub of his left arm, amputated just above the elbow, to hold the paper in place. But he had forgotten again how light and unmanageable the stump was. The paper skidded and the pen left a long black streak and a blot.