South Korean fantasy-horror series The East Palace introduces viewers to a fascinating world of supernatural beings rooted in Korean folklore, with each spirit reflecting different forms of pain, resentment and corruption that refuse to disappear.

Rather than relying on a single villain, the series explores a wide range of ghostly entities collectively known as gwi, a Korean term referring to ghosts or malevolent spirits. As the story unfolds, audiences discover that not all gwi are equally dangerous, with their powers shaped by the emotions that bind them to the human world.

Among them are the gwi-shin, the restless spirits of people who died with unfinished business. The least threatening are the common-gwi, harmless souls who remain because they cannot let go of a loved one, a promise or a responsibility. They linger quietly without posing harm to the living.

More dangerous are the won-gwi, spirits consumed by deep resentment. Their anger becomes so overwhelming that they lose their identities, remembering only the injustice they suffered. In The East Palace, these ghosts appear in disturbing forms and can only find peace once the wrongs committed against them are finally resolved.

At the top of the hierarchy are the ak-gwi, the most terrifying of all. These evil spirits are either cruel individuals who carried their wickedness into death or vengeful ghosts that have become corrupted after years of inflicting harm. Unlike other spirits seeking closure, ak-gwi exist only to spread destruction, making them the greatest supernatural threat in the series.

The show also introduces gwi-mae, creatures that differ from ghosts because they were never human. Formed from negative energy instead of human souls, they cannot be reasoned with or released through traditional exorcisms. They thrive in places filled with greed, fear and corruption, feeding on the life force of those around them.

One of the most memorable creatures is the Ggeomeoksali, an oddly adorable yet mischievous spirit that follows ghost hunter Gu-cheon (Nam Joo-hyuk) everywhere. Instead of simply draining his energy, the creature also develops a habit of stealing his snacks, providing moments of comic relief amid the show’s darker themes.

To battle these supernatural beings, Gu-cheon relies on sacred weapons tied to Korean traditions, including swords made from peach wood and rare lightning-struck jujube trees. Shamans also use protective talismans and sacred ropes to ward off evil spirits. However, the series emphasizes that weapons alone are not enough, as the strongest ghosts can only be defeated by confronting the hatred and unresolved pain that created them.

Ultimately, The East Palace suggests that the greatest source of evil is not the supernatural itself. While ghosts and monsters haunt the palace, it is the ambition, lies and resentment of the living that continue to give them life, making the series as much a story about human nature as it is about spirits.