This just occurred to me..
The Fated Children are killing the entire succession of witches as they travel through Time Compression or whatever effectively killing each Sorceress and aiding Ultimecia to absorb their fraction of the Sorceress Power. This also explains why no one has seen a Sorceress since Adel... They may not have necessarily been 'in hiding'. And this is how they passed on their power, where as the only way Edea recieved her power was from Ultimecia herself and thus began the Fated Loop.
This also leads me to believe that Ultimecia was not truly insane the whole time but was rather still absorbing Sorceress Power(s) when the Fated Children arrived and it was driving her insane at that point or at least disoriented as displayed by both Rinoa and Edea.
In effect... "Fufu". :love: