Rankers make about 30% percentile of the world's population. These rankers could choose to join either of four things as they pleased.
One, The Tower (similar to a law enforcement agency like cops, FBI's and special agents), which was a monolith that brought about peace and order to the world. They have various branches across the world and the rankers that are drafted there or apply to join their ranks are given the permission to catch criminals, dark guilds and rogue rankers that threaten the peace of their respective nations. They are even permitted to kill if the situation requires it.
Two, Guilds. The rankers from here are tasked with delving into fissures, clearing its monsters and ensuring the safety of citizens from a possible fissure overload. Large guilds often claim fissures as their own, using the resources gotten from it as an avenue to gather fame, prestige and wealth. Lots of wealth.
Three, Dark Guilds. Guilds who are on the other side of the law and perform various acts of illegal activities such as smuggling, terrorism, murder, assassinations e.t.c. Dark guilds have been around as far back as when mana had come to this world.
Four, none of the above. Some rankers just want to live their lives normally without the thrill of constant fights and battles.