The lyrics in the Latin songs from FF8 contain a chorus of "Fithos Lusec Wecos Vinosec". This particular phrase is not Latin, it is actually an English anagram. Composer Nobuo Uematsu created this anagram to represent the major themes of the game: Succession of Witches and Love. This is why the chorus is often played while Witches are in the foreground.
The power of each Witch can be passed on through Embodiment. Through this, Witches' powers from many generations may cross over to give one Witch great strength. Not anyone is a candidate for Embodiment, candidates need the affinity and capacity for that much power for it to be possible.
It's hard to determine how many Witches exist, for many keep their powers concealed. It is believed that they avoid spreading their power too thin. Witches like Adel who became widely known for cruelty have turned Witches into an object of fear for many people.
Despite their power, Witches cannot live forever. They must become fully human and free of their powers in order to die in peace. To do so, they pass all their powers onto someone else who can accept it.
Both Edea and Rinoa have a natural capacity for power. They have also inherited and embodied powers from other Witches, making them stronger than usual. Edea mentions late in the game that aside from Ultimecia 13 years ago, she received the powers of the Witch before Adel at the age of 5.
"Even if Ultimecia is defeated, it won't change the fact that she was born. My powers will be carried on across generations and eventually reach Ultimecia. What does it mean to inherit Ultimecia's power?"
–Rinoa on the Ragnarok
One motif that connects all Witches is wings. Depending on the Witch's heart, the colour of their feathers change. Edea has black feathers on her clothes while her back piece sprouts out much like wings, both Adel and Ultimecia have black spiky wings, and Rinoa has off-white ones.
The coloured designs on the Witches' faces and skin is make-up, while they are able to change their hair length or style at will. Although Witches are able to change their outer appearances, those who have become corrupt are unable to hide certain physical deformities.
Edea's face had prominent veins and her hands became elongated when she was without a Knight. As well, after her body was possessed for some time, her eyes became yellow just like Ultimecia's unnatural colouring. Adel grew inhumanly large with unnatural colouring and looked masculine, much like the Witches fought in Time Compression.
The Witches' Knights exist to support and protect the Witch's heart. They remind the Witch of the part of herself that is still human. It is proven historically that the goodness or evilness of the woman who became a Witch depends on her having a Knight.
Witches have many supernatural abilities which make them a potential threat to humans. They can use telekinesis to move anything, including people like dolls, move objects and space at the molecular level, and easily brainwash people at a subconscious level to do whatever they want. They also have the ability to junction each other and drain the other's strength.
Some high technologists in Esthar have been studying Witches, including how to suppress them. A Doctor named Odine originally researched monsters and GFs but later took special interest in Witches and Magic. With Adel's permission he even researched and wrote the Manual for ordinary humans to use Para-Magic and GFs.
In fear of Adel's power, Doctor Odine created Odine's Goods. These goods come in the shape of beautiful accessories for women and they seal a Witch's magic when worn. A similar high tech device was Adel's Tomb, which was launched out of the atmosphere and near the moon. It was created to encase a Witch in a reduced-power stasis, more reduced than when in the Witch Memorial.
A legend exists in FF8's world, that the Great Hyne is the creator of mankind. Hyne was losing a war with the humans he created and escaped by leaving them what is referred to as Hyne's castoff power. It was half of his power that was discarded, a savage and vulgar half.
The power caused the humans to become corrupt and fight among themselves for it, allowing Hyne to run away with the better half. Those who were born Witches were given a fragment of this half of Hyne's power. It's unknown what had become of Hyne but it's believed that he is still hiding and watching the humans.
It is likely that Hyne's castoff manifests itself in the form of wings on humans, as the feathers often seen shedding from a Witch seem to have a will of their own in the game. Since Hyne was the first Witch, addressing a Witch as the Great Hyne's descendant is also considered a sign of respect. For more about Hyne, see the Impressive Words section.
Ellone was born with the ability to use a special kind of Time Magic and the natural capacity to inherit a Witch's power. Connect is what she calls her ability to allow people to experience the past by sending one's consciousness back in time. What she didn't know was that this ability allows a Witch from the future to completely control a Witch from the past.
By travelling to the various states of present which have become compressed, a Witch can take control of another Witch's body in that time. If she used Ellone's power, Ultimecia would have been able to go even further back in time than the generation of Edea, Rinoa and Adel – which was the generation she reached using Junction Machine Ellone.
By using the Witches' powers from all those generations crossed over, Ultimecia would then be able to achieve great strength by compressing the past, present and future using her magic. It's not known exactly what will happen but Witches believe all existence would cease. That is, all existence except for the Witch who achieved it and in theory she would become as strong as Hyne.