Unexpected Immortal

A character previously thought to be a normal mortal becomes immortal (or near-immortal) by some means, depending on which universe this is set in.

Winning Is The Only Safety (1) First Death by Kathryn A ( Blakes 7 / Highlander Prose ) [1995] (34K 5982 words)
PGP crossover. With so many corpses on Gauda Prime, what's one body more or less? Avon and Vila are both free, alive, and alone. How long can this last? And what strange thing has happened to Avon? ( Crossover , Unexpected Immortal , Post-Series )
Complications by Kathryn A ( Torchwood / Doctor Who Prose ) [2008-06-12] ( 4900 words)
They hadn't checked to see if there were any side-effects. (AU. Set just after 'A Day In The Death'.) ( AU Divergent Timeline , Unexpected Immortal )