Variant

Variants (バリアント, Barianto) are among the main focus in the series.

Description
After the arrival of the savages, a virus came alongside them as an airborne toxin, which had infected humans in a number of ways by either making them sick or letting them react to the Hundreds known naturally as Slayers, special humans able to fight against the savages. On the other hand, the Variants are a unique group of humans who came into direct contact with the savage's bodily fluids by either being attacked or injected into their bodies, then survived the process.

There are three known kinds of variants:

Natural Variants were infected injected by the Variant virus straight from the Savages themselves and survived the process. Another method is by receiving the variant virus from a Natural Variant.
 * Serivia Notredame
 * Emilia Gudenburg
 * Hayato Kisaragi
 * Vasily Tynyanov

Artificial Variants were injected using a modified variation of the savage virus or by using the variant virus from someone else.


 * Sakura Kirishima
 * Nesat Olfred
 * Krovanh Olfred
 * Nakri Olfred

Born Variants is a special kind of person who was injected using a modified version of the variant virus before their actual birth. There was one person who was born in this manner headed by Linis who altered it on a genetic level to demonstrate the highest intellect and physical abilities.
 * Liza Harvey

Controlling Method and Transference
The variant virus can be transferred to another person, a basic method being through ones' saliva (via kissing), which can assist another variant in controlling their abilities and it is also possible to give a normal Slayer variant powers for either a limited amount of time or even turning them into a variant. Using the variant virus of a natural Variant or even from a savage, it is also possible to create an artificial variant.

As shown by both Hayato (unintentionally) and Serivia, it was possible to infect someone with their variant virus by kissing one on the forehead; which could either improve their natural condition as shown with Karen Kisaragi who was stuck in a wheelchair due to the virus that the savage brought; and even turning someone into a variant through constant contact as shown with Marko and Luka.

Appearance
Variants maintain the same natural appearance of normal humans, the main difference is that their eyes turned a bright golden when using their powers. However, in the anime, it was shown that when using their variant powers, their teeth can become sharper.

Powers and Abilities
All Variants have enhanced abilities compared to that of normal Slayers, most of which are even considered to be geniuses such as Claire Harvey. The most notable among them being that variants have a higher reaction score compared to others, as first shown by Hayato who after taking an aptitude test during the Warslan Festa, in which a red light that had covered the entire area even turned into a sword causing people around him to refer to him as a "prodigious slayer".

Another one being through the activation of their "variant powers", a variant attained enhanced power at the cost of draining more of their energies.

Weaknesses
Despite their great powers, there are several major weaknesses for a variant, the most notable being that if they are unable to control their powers they enter a state referred to as "Raging Berserk", which causes them to lose control and go berserk. This could result in death or serious injuries similar to what happened to Gert Abramovic, however, this can be better controlled through controlling ones' Sense Energy.

Despite their similarities, Artificial Variants are weaker compared to that of Natural Variants.

Trivia

 * Variants are rare as Emilia noted that there were around 10 variants in the world.
 * Those who are variants are said to possess the "Blood of God".