🚀 go-pugleaf

My guess is that she's Satan Girl, a Supergirl-clone/duplicate/whatever
who fought the Legion early in their career and was de-powered by exposure
to gold kryptonite.  I haven't gone to the trouble of checking for clues
that would prove this, but (WARNING! LOGICAL FALLACY APPROACHING!) my track
record is pretty good for Levitz/Legion mysteries: I knew Darkseid was
behind the Great Darkness, and figured the shooting of Laurel Kent and the
killing of the PI who was descended from Batman were both committed by a
(descendant of a) JLA villain (although I think Levitz and Giffen copped out
by not naming a specific villain whose Modus Operandi could have been 
recognized).

Unfortunately for me, it'll be a least a year before I read the issue wherein
All Is Revealed.  DC's recent price hike for their deluxe comics forced me
to choose the cheaper (half-price now!) non-glossy "reprints" of the Legion,
the Outsiders, and the Teen Titans.  (And I'll probably forego the 
disappointing Infinity, Inc., until I can pick up back issues in local bargain
bins.)

Chris