Rarely in fiction is shown what kind of trials and tests bad guys (villains) go through to become what they are. Good guys have wise teachers who at worst are harsh and secretive, but still teach. Bad guys must slave under brutal terror of vastly more powerful bully and maybe gather some scraps of knowledge from their relentless thuggery towards them, yet they persevere as well. Even when bad guy really teaches somebody they always withhold important things.
Evil-Lyn was canditate for Sorceress, but for some reason or another she failed that purpose. Maybe she abandoned her children during her search. Maybe she is barren and despite constant attempts never had a child of her own. Heart filled with bitterness and jealousy she sought dark magic and has proven very adept.