"Kigurumi Guardians" centers around a group of high school students who are unexpectedly thrust into a battle to protect their world from malevolent creatures known as Shadows. The story begins when the protagonist, Haruto, discovers a mysterious kigurumi (animal costume) that grants him the ability to transform into a powerful guardian. Alongside his classmates, who also find similar kigurumi, Haruto forms a team to combat the Shadows, which are manifestations of negative human emotions and threaten to engulf the world in darkness.

Each character’s kigurumi represents a different animal and grants unique abilities tied to their personality and inner struggles. Haruto, as the leader, embodies the lion, symbolizing courage and determination. His closest friend, Yuna, transforms into a fox, representing cunning and adaptability. Other members include Riku, who takes on the form of a bear, embodying strength and resilience, and Aoi, whose rabbit kigurumi reflects agility and sensitivity. Together, they navigate the challenges of balancing their ordinary lives with their responsibilities as guardians.

The narrative explores themes of teamwork, personal growth, and confronting one’s fears. As the story progresses, the characters face increasingly powerful Shadows, each requiring them to confront their own insecurities and emotional wounds. The Shadows often target individuals harboring intense negative emotions, forcing the guardians to not only fight physically but also to help those affected overcome their inner turmoil.

The series delves into the origins of the kigurumi and the Shadows, revealing a deeper connection between the two. It is gradually uncovered that the kigurumi were created by an ancient civilization to combat the Shadows, which were inadvertently unleashed due to humanity’s growing negativity. The guardians must uncover the truth behind this ancient conflict while preventing the Shadows from spreading further.

As the stakes rise, the group faces betrayal, loss, and moral dilemmas, testing their resolve and unity. The story balances action-packed battles with moments of introspection, highlighting the characters’ development as they learn to harness their powers and work together. The final arc culminates in a climactic battle against the source of the Shadows, where the guardians must make sacrifices to protect their world and ensure a brighter future.