Teiresias' Kin: Blossom and Thorn
Teiresias' Kin: Blossom and Thorn is a story written by Delyth Penrose. It ran in Issue 21 at http://s2b2.livejournal.com/115927.html, and is mirrored at http://www.shousetsubangbang.com/mirror/teiresias-kin-blossom-and-thorn/.
From the author: "Meeting Gwion and Gilfaethwy, Arion, and their Imperial captors, including Aenfrith ec Saelwine and his house-slave Eathlwine. Approximately concurrent with the first part of Teiresias' Choice."
From http://ciraarana.insanejournal.com/27574.html: "Aenfrith, to the Imperials known as Flavius, takes in three magically gifted - and changed - prisoners."