Conversation so far:
What was New Excalibur?
The letters page of the final issue of Excalibur announced a relaunch of the title as New Excalibur in November, 2005.
Is New Excalibur a group?
New Excalibur is a fictional superhero group appearing in Marvel Comics. They are depicted as an offshoot of the X-Men, usually based in the United Kingdom.
What happens after the New Excalibur and Sage win against Albion?
A party is held in honor of Excalibur.
Did the New Excalibur and Sage defeat anyone besides Albion?
They defeat Merlin, but not before he manages to kill Roma.
What about Sage's persona in New Excalibur??
Sage creates the new cover identity and persona of Diana Fox. This persona appears to be fully devoted to Albion and his goals.
What happens after Sage's new persona, Diana Fox, is released?
Her Diana Fox persona climbs up the rank of Albion's Shadow Captains as Britannia, and develops a rivalry with Lionheart.

Question: Does she turn on them?
Self-contained rewrite: Does Diana Fox turn on the New Excalibur?