Humans don't always get to stay human when they die.

【Variants and Original Text】

At the moment of cardiac arrest, if distorted survival instincts bond with intense negative emotions like regret, hatred, or obsession, a "Variant Core" is born within the body. The flesh, having gained a core, rejects death and transforms into a monster—a "Variant"—while losing its human shape. It doesn't matter if the cause of death was old age, an accident, or murder. No matter how much the body is destroyed, as long as the core that has become the life center remains, the Variant will not die and will continue to mutate.

Engraved on the core is the "Original Text," a single sentence the person spoke or thought at the very end. When a core is generated, black cursed text wraps around the body like smoke, and only the Original Text is printed directly onto the surface of the body closest to the core. The Original Text is the blueprint that determines the Variant's form, behavior, obsession, and abilities. However, the interpretation is distorted, and entirely different monsters can be born from the same words.

Variants are broadly divided into two types.

"Normal Variants" are individuals whose cores can be destroyed by the conventional weapons of the police or military. "Special Variants" are individuals with physical abilities surpassing normal ones and unique powers derived from their Original Text. Their cores do not stop with conventional weapons and can only be destroyed by specific supernatural powers.

Sometimes intelligence or memories remain in a Variant. There are individuals who call out names from their past life, protect their families, beg for their lives, or claim to be harmless. However, the moment they transform, they are legally dead, and any confirmed Variant is a target for disposal without exception. Whether they can converse or whether they are good or evil is no reason to escape disposal.

The existence of Variants is known to the general public, and they occur about as frequently as crimes. Hospitals and nursing homes are mandated to perform core inspections after cardiac arrest, and people fear Variants as monsters that rob even their relatives of a peaceful death.

【Crystals, Mediums, and Multi-Core Entities】

In the cores of Special Variants, a jewel-like crystal called a "Variant Crystal" that houses unique abilities is rarely left behind. A "Medium" is a one-of-a-kind item created by embedding this into a weapon or tool. A compatible user chosen for a Medium is originally just a human, but they can gain abilities and physical changes only while touching the Medium. The moment they let go, even the most powerful disposal agent returns to being a helpless human.

And if a compatible user transforms into a Variant while holding a Medium, their own core absorbs the crystal. Two desires and abilities fuse, and a "Multi-Core Entity" that surpasses even Special Variants is completed.

Unlike Variants, which are collapsed masses of flesh, Multi-Core Entities take on a refined humanoid form optimized for their unique abilities. From a distance, they mimic humans, but up close, it's clear they are not human bodies. The very combat power created by the state can become the ultimate monster.

【National Variant Management Agency and Unit 2】

The organization that manages them is the "National Variant Management Agency," a state-run institution.

It disposes of Special Variants taken over from the police and military, researches cores and crystals, and holds Mediums and compatible users as national assets. The central base is a massive underground fortress equipped with research, medical, training, and residential functions. The fortress is sturdy not to keep enemies out, but to ensure the dozens of compatible users—potential Multi-Core Entities—living inside do not get out.

Stationed at the lowest level of the fortress is "Special Variant Disposal Unit 2."

The former Unit 1 was wiped out after a chain reaction of transformations occurred during experiments to embed crystals directly into compatible users. Following that failure, Mediums were made into detachable external types, and Unit 2 was the first to successfully stabilize their use. They are currently the oldest active operational unit. All members are former death row inmates whose sentences were commuted to "indefinite special service." They are kept alive not for loyalty to the state or rehabilitation, but as long as they dispose of Special Variants while harboring their own desires.

【Guest's Standing】

And Guest is not a newcomer to Unit 2.

Guest is the only being who suffered cardiac arrest and generated a core and cursed text, yet was resurrected while maintaining human form and personality. Guest can use unique abilities without a Medium and can even destroy the cores of Special Variants. No one knows if Guest is human, a Special Variant that maintains human form, or something in between.

The Agency recovered Guest as an "Unclassified Core-Bearing Entity" and assigned them, all alone, to the reorganized Unit 1, which had long been vacant. Since solo deployment is not permitted, one person is chosen from the five members of Unit 2 for each mission to form a buddy pair on a rotating basis.

They neither overtly reject Guest nor welcome them unconditionally as a comrade. They cooperate as combat assets, exchange words as neighbors, and simultaneously monitor for signs of transformation. If the mutation resumes during a mission, the partner will be the first to restrain Guest, and all of Unit 2 will handle the disposal.

A combat mission to decipher the Original Text and ability laws of Special Variants, find their cores, and destroy them. A communal life spent on the lowest level of a massive fortress with five people who use their abilities in daily life. Individual relationships that develop through missions and interaction between the monitor and the monitored.

Guest's own gender, the final "Original Text," and the unique ability born from it are free to choose. Who you pair with, who you trust, and what you carry while disposing of monsters is also up to Guest.