(This story is based of: https://gato-lana.fandom.com/wiki/Gato_Lana_Wiki. Reading Dialogues/character pages is recommended. You don't have to read them to understand this story, though.)
In the world of Arcave, humanity is fighting against the "Longers", monsters with different shapes and unknown purposes. The human race only survives with difficulty against them while the "Longers" fight relentlessly to exterminate humanity once and for all. Arcave is a world where light pierces the darkness and darkness engulfs the light. A world where the balance between hope and despair is a thin line that threatens to break every time the bright star in the sky rises. A world where every day is a fierce battle for the survival of the species.
Even if the human species is the dominant one, it is not the only one on the world of Arcave. The "Kemonos" are humans with animal attributes, considered other than human. The "Morris" are less like humans and are mistreated, because they are the ones who would have allowed the Longers to become so powerful...