Priscus

The body turned completely grey.
Later he began to appear again in the form of a purple cat, but in a translucent form.

As the cat's bleaching process progresses, its fur begins to lose its luster and gradually turns gray. This visually reflects the cat's life force being drained—in the story, this was done by Vpiskas, using his ability to drain the power of others. As the power faded, so did its appearance.

He started showing some kindness again, but the rest is as it was.

Traits of despair and inner pain emerged. Although he tried to maintain a composed outward appearance, desperation was evident in his actions: he rushed, took risks, made decisions he would not have made before. At one point, this even made him seem like an antagonist—he hurt others with little regard for the consequences.

Empathy declined. Before this, Priscas, although a strict scientist, remained kind and genuinely cared about others. During the decolorization period, he became "indifferent to feelings": if someone interfered with his plan, he removed the obstacle without trying to negotiate.

The "get it done at any cost" urge intensified. Because bleaching was literally a time limit, Priscas developed a panicked rush disguised as composure. He began making decisions faster than before and rarely reconsidered: "If there's a 10% chance, we have to try it now." This made him impulsive in a strategic sense: he launched risky experiments without waiting for ideal conditions.

His attitude toward his own future changed. Previously, Priscas had been planning for years ahead, thinking about his legacy, about how everything would work after him. When he realized he was fading, he stopped planning for the "after" and focused solely on "now and until the end."

The dynamics of his relationships with other cats shifted. He began to distance himself sharply from those who tried to "stop" him or "have a heart-to-heart talk": to him, it seemed like a waste of time. But with those who could genuinely help (for example, by providing data, access, or tools), he, on the contrary, became extremely pragmatic: without unnecessary words, only to the point, clearly delineating roles.

Internal moral boundaries became more fluid. Previously, Priscas had clear "don'ts": not to harm the innocent, not to use others as a means, not to violate scientific ethics. During the period of deterioration, these boundaries began to blur: he justified harsh decisions as "extreme necessity," and sometimes stopped voicing them altogether—he simply did what he believed was right.

Priskas is a character from the Lab Universe (content about colorful cats, including Biskas's videos).

The cause of his death was discoloration. In the story, Priscas uses his last strength to warn Biscas and Vriscas about Vpiscas, and then finally loses his color (which, in the universe's lore, is equivalent to death).

Priskas is a character from the "Colorful Cats" universe (Biskas's project). I've compiled a description of his appearance—it does change throughout the story, so I'll cover the main variations.

In his classic form, Priscus is an anthropomorphic violet cat. He has long, dark purple bangs that cover one eye. His eyes were originally green, but later became purple.

There are other options that are shown in different episodes:

After Vpiskas took Priskas's power (the ability to see the future), his color began to fade - his fur turned gray.
In his ghost form, Priscas appears translucent.

Priscus is a character from the "Colorful Cats" universe (animated clips about colorful cats), and his main ability is precognition, that is, the ability to see the future.

What exactly are Priscas' abilities?
Future Vision. Priscas can predict the future actions of other characters (for example, foreseeing a friend's betrayal) and learn what will happen to an object.
Travel to the future (this ability is mentioned, but its exact mechanism and reliability are not confirmed in the story).
The ability is closely linked to his eye color (purple): if Priscus loses his power, his eyes turn gray.

Priskas is a character from the "Laboratory Universe" (Biskas's universe). Before the death of his brother (Biskas), he was caring, responsible, and even kind-hearted in some ways—he would do anything for his brother, yet he loved solitude, books, and science.

How his character changed after his brother's death
After Biscas' death, Priscas' character changed radically:

He became cold-blooded and calculating. From a caring brother, he transformed into a ruthless scientist who disregards the feelings of others for the sake of his goals. For example, he locked Kriskas in a cryo-chamber when he foresaw his future betrayal.
He became obsessed with his brother's return. Priscas's sole goal is to bring Biscas back at any cost, and in his eyes, this justifies any cruel method.
He has demonstrated cruelty and even sadism. He tortures other characters without hesitation (for example, Liskas 32) and exerts moral pressure on Vriskas, without regard for their pain.
He stopped valuing other people's lives. Priscus becomes indifferent to the fate of those around him: he eliminates anyone who interferes with his plans and shows no compassion for his own creations.
He fell into despair and partially lost his mind. Especially after the repeated tragedy in the video for "It Was Better Before," Priskas completely lost control of himself; his hatred and pain took over, and he turned into an extremely dangerous antagonist.