1. Worldview

Humanity was suddenly invaded by an alien race called the "Astra."

The Astra possessed scientific technology far superior to that of humans. However, it wasn't just technology that drove humanity to despair.

Every single Astra individual possessed transcendent abilities.

Bodies that could withstand bullets bare-handed.

Speeds that the human eye could not follow.

The ability to freely manipulate fire and lightning.

Power to interfere with space and matter.

Humanity's armies could not even mount a proper response.

After years of war, humanity lost most of Earth's territory, and the population decreased drastically.

Just as humanity was pushed to the brink of extinction, a miracle occurred.

A mysterious substance brought by the Astra to conquer Earth.

"Aether."

Aether was a substance closely related to the Astra's supernatural abilities.

And the Aether spread throughout Earth's environment began to resonate with the bodies of some humans.

As a result, supernatural abilities manifested in humans as well.

For the first time, humanity gained the power to fight the Astra.

While they couldn't completely turn the tide, they could at least avoid extinction.

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2. The Last Cities

With most nations and cities collapsed due to war, there are only six large-scale survival zones maintained by humanity.

Seoul Tokyo London New York Los Angeles Paris

Each city moved underground and was rebuilt around an academy, and supernatural academies were established to train and manage ability users.

These are not typical schools.

They teach the control and application of supernatural powers, as well as combat against aliens, tactics, survival, and rescue operations.

The students are all adults.

After graduation, they are deployed to the military, government agencies, research institutes, and defense companies to fight for humanity's survival.

And if an alien attack occurs, the academy immediately converts into a combat base. However, since a frontal confrontation is suicidal, the top priority is remaining undetected.

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3. Supernatural Ability ― 「Sync」

Supernatural abilities are not powers humans are born with.

They are transcendent phenomena that occur when Aether resonates with the human body.

The form of the ability is completely different for each individual.

Some handle flames, some manipulate gravity, some sever space, and some enhance their own bodies.

Even for abilities of the same type, the manifestation method varies depending on the user's body and mind.

The Academy is divided by grades based on a strict meritocracy. The grades are in the order of S-A-B-C-D-F.

Sync

A state where one resonates their body with Aether to manifest a unique supernatural ability.

This is the basic state used by ability users in combat, and most ability users spend their lives honing their powers within Sync alone.

While they can develop ways to utilize the ability itself or create new techniques, the fundamental framework of the power is maintained in the Sync state.

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Over-Sync

The final release that completely aligns the essence of one's ability with Aether.

It is not a simple output boost.

The moment Over-Sync is activated, the essence of the ability is fully revealed, and the power transforms into a new form.

The manifestation form is completely different for each user.

• The range of the ability can expand overwhelmingly.
• The nature of the ability itself can change.
• New abilities can be added.
• The user's body may change to suit the supernatural power.
• Existing techniques may be restructured into Over-Sync exclusive techniques.

In short, Over-Sync is the 'completed form' of the ability used in Sync.

And very few humans reach Over-Sync.

Among the numerous ability users, those who have reached Over-Sync can be counted on one hand.

Therefore, Over-Sync users are treated as the top-tier military assets possessed by humanity.