Soul Core

A soul core is a star hanging above an Awakened's soul sea. It was supposed to be burning with bright light filling the sea of soul with blinding shine.^[3]

It was unclear why the Spell had eventually decided on youngsters aged sixteen to eighteen after devastating the First Generation indiscriminately. Back then, humans believed that younger people were more likely to survive their first nightmare, possibly due to the difficulty of forming a stable core after becoming set in its ways. This could lead to an older person dying after their soul collapsed while trying to create a core.^[4]

Awakened battles were tactical, with essence restoring itself to its maximum capacity. It was a finite resource, requiring careful use and absorbing soul fragments to increase core capacity.^[5]

There are some Awakened with unique soul constitutions. Some Awakened have abilities like a soul core that can grow continuously without the usual limitations, or the ability to form multiple soul cores similar to Nightmare Creatures.^[6]

Unique to Sunny due to the special nature of his aspect. It looked like a black sun but actually, it was transparent with no major source of light.^[3] By directly killing the enemy, he can instantly absorb a part of their shadow and enhance his own core. That meant that shadow fragments could not be stored, and subsequently could not be bought or traded.^[7]

Since both Sunny and his shadows were tied to the Shadow Core, strengthening it would not only increase Sunny's power but also enhance the shadows.^[7]

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A soul that had a core had many advantages, but it also had to bear weight. Not every soul has the strength and size to support even one person, much less several. The terrible pain Sunny felt each time his class rose was evidence of it.^[4]

When a new core is born in the depths of their soul, it comes with the pain of their soul being torn apart.^{[10][11][12][13][14][15]}

• Rain's Soul Sea

This soul core is a bit special as one's soul is deeply connected to the essence of the world. Thus, have access to a form of spirit essence. Unlike soul core saturation, this spirit essence does not directly enhance one's physical strength, but it is still under one's control. Over time, this connection has manifested in one's Soul Sea.^[6]

Through a mysterious process, the formless state of a mundane soul was being galvanized, slowly creating a more solid shape. A soul core was not a soul, but it existed within the soul, serving as both its fulcrum and nexus. These streaks flowed to the chest and swirled, slowly merging into a sphere of brilliant light. As the sphere grew fuller and more defined, the familiar shape of the soul core started to emerge from the brilliance.^[4]

The nascent soul core exploded with a flood of ethereal flame, which rolled through the body as a radiant wave, rejuvenating it. After the soul core was formed, faint streams of weak essence coursed through the body. The body itself was being rebuilt by it, growing healthier and stronger, getting one step closer to perfection.^[4]

A seed of darkness appeared in the center of the forming core. It quickly expanded, spreading like a cancerous growth. Repulsive veins of darkness spread through the dying light, consuming it. The more light was consumed, the faster it spread. The Corruption spread through the body of the man, becoming one with it. Then, the body started to change into a Nightmare Creature.^[4]

One needs to control their soul essence by guiding it throughout the body, following the roadmap of major blood vessels. Through one's will to guide the essence in flowing slowly in a complicated cycle, increase the speed of the essence, making it rush like a mountain river and spinning inside their body like a raging whirlpool. The essence condenses under the pressure of its weight and the pull of the rotation. Making the essence circulate faster, eventually reaching a critical point where a soul core will be formed. A condensed mass of energy slowly formed in the place where their heart would have been, not solid yet but more like a shimmering liquid. At the very center of this mass, a tiny crystalline gemstone is slowly being born.^[16]

• Corrupted Soul Core