Japari Park is an untamed paradise where many humanoid animals, known as Friends, live their everyday lives in all corners of the natural environmental park. One lazy afternoon in the savannah area, the energetic Serval encounters a peculiar new Friend. Curious, she swiftly takes down the Friend, named Kaban, to try and discover what species she is. To Serval's disappointment, not even Kaban herself knows the answer. The two become friends and set out on a grand adventure through the many habitats, landmarks, and attractions of Japari Park. Their destination is the park library, where they hope to shed some light on Kaban’s identity. Along the way, they meet many other Friends, looking into their lives and helping them out. However, they soon begin to uncover the sinister reality behind the park and their own existence.

Ninja... Ninja were... merciless demi-gods, ruling Japan with their karate in the age of ninja tranquillity. But, some committed a forbidden form of hara-kiri storing their souls at Kinkaku Temple for future resurrection. Their lost history was falsified and concealed and the truth about these ninja was long forgotten. Now, in the future where the universalization of cybernetic technology and electronic networks are God, suddenly, sinister ninja souls, resurrected from thousands of years past are unleashed on the dark shadows of Neo-Saitama. Fujikido Kenji, is a salaryman whose wife and child were killed in a ninja turf war. In a brush with his own death, Fujikido is possessed by an enigmatic ninja soul. Fujikido cheats death and becomes Ninja Slayer. A Grim Reaper destined to kill evil ninja, committed to a personal war of vengeance. Set in the dystopian underworld of Neo-Saitama, Ninja Slayer takes on Soukai Syndicate ninjas in mortal combat. (Source: Animanga wikia)

In a futuristic era, The World is a peace-bringing entity. Though no one knows its location, it has watched over Earth for so long that war has become merely a fable. The airship Norn's task is to deliver nine ability users to The World. After collecting the last person, Norn takes off. Included onboard are eight men and three women—Koharu, who has finally escaped her loneliness and detests her destructive power; Mikoto Kuga, born to a noble family, who uses her barrier skill to protect the Norn and those it carries; and Nanami Shiranui, whose ability only brings pain, and who wishes to die for a past sin she has committed. While en route, suspicions arise amongst the passengers when they realize there are too many people onboard. As they try to determine who has snuck aboard, the ship is attacked by an unknown assailant aiming to stop the Norn's progress at all costs. From this chaos arises questions: why were they granted powers, and what must they do once they reach The World?