Well, the shinobi rules in Naruto fanfic can be quite diverse. There's the rule of secrecy regarding jutsu. Shinobi are not supposed to freely share their unique and powerful jutsu with outsiders or enemies. Then there's the code of honor in combat. They should fight fairly, not use underhanded tactics like attacking an unarmed opponent. And of course, they are required to respect the hierarchy within the village's shinobi system.
Hell's Paradise is a story full of action and adventure. It mainly follows Gabimaru, a ninja on death row. He is sent on an expedition to find the elixir of life on a mysterious island known as Shinsenkyo. Along with other criminals and executioners, they face various deadly threats and challenges on the island.