The Pitch Plague

The sickening plague based on the energy of Sko, often spreading from twisted pitch black roots.

One origin point for the disease being the Guardian of Decay, Thora, landing on top of the city of Sygnal after losing the battle against Petra, her disgusting corpse like body spreading the plague swiftly

Infected Victims

 * Twilight
 * Thora
 * Nera

Symptoms
The roots burrow under your skin and inject you with Sko, then spreads through the blood, entering the brain and slowly destroying it, reducing your average victim into a feral and mindless husk.

Most of the time, individuals infected with the Pitch Plague gain feral and bloodthirsty personalities, turning any creature it infects into a wild, murdering, unthinking beast. Originally, it was thought this happened to all alanothean or alien creatures, but time proves otherwise. Some creatures simply die after some time when infected, or retain some of their former intelligence in a crazed half-existence. There is even documentation of a religion based around intelligent infected trying to become un-infected, believing that they were infected because they were sinful.

All infected have a couple things that are the same: They're all pitch black with glowing white eyes, they all spit an acidic black fluid from their mouths like a viper, and they all can become servants to those with lots of Sko in their soul. What I'm getting at is that symptoms differ. Sometimes creatures leak black fluid out of their eyes and/or mouth, sometimes they decompose like zombies, and sometimes there's coughing and wheezing. Most of the time, small black veins on the body is a sure sign you're infected

All infected also have black blood

Skotati take over humans, the infection kills them

And thats cause there's so much Sko that it's like acid, dissolving humans from the inside

But Skotati mind control humans and other creatures, bending them to their will

The Pitch Plague, a sick virus carrying large traces of Sko, origins are unknown but one known ground zero is the city of Sygnal, after the Guardian of Decay, Thora, had landing upon it, infected the entire city with her corrupting rot.

The most common way to become infected is via roots, carrying large amounts of corrupting Sko within, crystals can simulate the effects of the roots, with the Lunar Eclipse amplifying their effects.

Victims eaten by any being infected by the shadowy plague will slowly become corrupted themselves as well.

It turns them into blood thirsty killing machines, devoid of humanity and thought. They don't remember their past lives, and any smell of the living drives them to kill. Visible signs include a very monochromatic black and white coloring, their blood turning into an inky oil like substance, losing their old form. Some being are capable of some intelligence, but others like Twilight are completely feral, becoming more like violent dogs.

Dragons are typically converted into feral abominations, smaller humanoids are often melted down, but crystals and artificial infections created by the sadistic scientist known as Xevi-Zu can simulate the effects of the virus in folk like humans, anthromorphs, and Mobians who would all otherwise rotted away.

The roots won't target someone if they are deeply corrupt to the core.

Twilight herself is now no longer a dragon with free coherent thought, she's now a feral beast with the mindset of a bloodthirsty animal, liable to tear apart any living creaure she comes across, chewing on their bones like a dog, following around and being beholdent to horrible people like Kira, Cahaya or Pali.