In a world where mysterious cracks called Rifts have opened across the earth, monsters from unknown dimensions began invading. To fight back, humanity developed a global virtual network called "System Online." It connects to people's emotions and awakens special abilities based on who they are deep inside.

Every person who awakens gets a unique system tied to their personality, feelings, or past. These systems can grant powerful abilities—but they come with risks. The stronger the emotion, the stronger the power. But losing control can lead to self-destruction.

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Lee Ji Han, a quiet and distant boy, has lived most of his life suppressing his emotions. He awakens with a mysterious system called the Emotion Core, which allows him to feel and absorb the emotions of others—and turn them into power.

But this ability is dangerous. If Ji Han absorbs too much... he could lose himself.

Together with Kang Ha Neul, a calm and sharp boy with the rare System Mirror that lets him copy others’ systems, and Han Ji Won, a hot-headed fighter with a system that feeds off rage and fire, they begin their journey as Rift Responders—people who fight back against the growing threat of corrupted creatures.

As they train, fight, and grow closer, they’ll uncover secrets about the systems, their own pasts, and the true reason the Rifts exist.

But in a world where emotions are power—
Who controls who?


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Rifts are like doors to another world. They are dangerous and unpredictable.


Monsters that come from Rifts are ranked based on how powerful they are:


What are people who clear Rifts called?


They are called Rift Responders or just Responders for short.


They're the ones who go into Rifts, fight monsters, and close the cracks before more damage spreads.


Just like monsters and Rifts, people are ranked based on their power and experience:


F-rank – The weakest. Just awakened. Still training.


D-rank – Basic fighters. Can handle small threats.


C-rank – Mid-level. Can work in teams to clear dangerous Rifts.


B-rank – Strong. Can fight alone or lead teams.


A-rank – Elite. Trusted to clear tough Rifts.


S-rank – Super rare. Almost legendary. Only a few exist.


EX-rank (optional): A hidden rank for unknown or unstable systems. Most people don't even know it exists.


Rift = A crack in space that leads to another dimension. Monsters come from here.


System = A power awakened through emotions. Everyone's is unique.


Responder = A person who clears Rifts using their system.


Ranks = A scale that shows how strong someone or something is (F to S, maybe EX).


Rifts and Rank