Thread:MMYP999/@comment-27109830-20170728220105/@comment-27416494-20170808190337

Sure, the Aselia Wiki is a good source of information for the series, but it is jarringly incomplete in certain sections from what I've seen.

As for Ultimecia and Shizel, both of them are powerful sorceresses fueled by anger and hate who share a similar goal of causing two world ending cataclysms known as Time Compression and the Grand Fall respectively. They're well known for possessing the bodies of other powerful sorceresses to do their biddings. (For the sake of clarification, Shizel herself is actually under the control of a vengeful God called Nereid, whilst Ultimecia has personally taken control of the the sorceresses Edea, Rinoa, and Adel throughout the course of Final Fantasy VIII.) They also share a unique ability to summon (or rather fuse with in Ultimecia's case) powerful guardian entities (The GF Griever and a manifestation of Shizel's shadow) to fight by their side.