Arthur, an orphan living on the street, finally unlocked the Animal Cultivation System on his 15th birthday in a post-apocalyptic world where humanity discovered cultivation through the Animal Cultivation System. However, his life did not change as much as he had hoped. Unable to find a strong animal to bond with, our MC ends up bonding with a Rat! Follow Arthur as he learns how to survive while being the rattiest under the heavens instead of the strongest! Note: The content warning is only there so I can write freely and might or might not be relevant depending on how the story develops! Update schedule: Once a day, there might be a bonus chapter depending on my mood or if we reach a certain milestone!