Quote Originally Posted by Big D View Post
She was purple before her imprisonment, as shown by Laguna's scenes. According to the FFVIII Ultimania, physical mutations are a side-effect of using a lot of dark magic.
Time-compressed world. The world wasn't TC'd before Adel started undergoing her imprisonment.

The moment when Ultimecia passes her own powers to Edea was the turning point of the TC process. That's how Matron looked very normal, so did Adel.