Another idea....

Mihoshi goes back into the very very very distant past somehow 
(either through the evil being's own power or by stealing one of 
Washu's devices.). In the past, she encounters a young man who 
is a decent well-mannered young man. Sensing he'll be a 
formidable foe if left alone, she tells him about the great 
power of Jurai and all it can do. Then causes a disaster to 
befall him, forcing him onto a quest for this great power. As he 
searches, the voice he's hearing (Mihoshi's) drives him deeper 
and deeper into power madness.

The young man's name?...


...Kagato.





Hachi zero hachi ichi ni zero ni kiyu.
Uchu kaizoku, Ryoko-dono.