(last updated: 12/28/17)
A fighter's ratio is an informal representation of where they are in their training and their overall power level in regards to other fighters. In the world as we know it, ratio is an uncommon, little-known term used in some minor tournaments and insurance documents, but roughly speaking, fighters are graded on a scale proceeding roughly from Ratio 1 (R1) to Ratio 5 (R5). Some legendary fighters have ascended to even higher ratio, but on average a person stands a better chance of being hit by a tornado than meeting these men and women.
There is a measurable difference between power and skill. Ratio is only a measure of the overall power of the individual--a fighter's skill is measured by their Class, not by their ratio. Some say that a fighter's overall power level is roughly consequential to their drive and influences in life; a fighter can train and hone their techniques endlessly, increasing their breadth of skill, but his or her maximum potential can often only be brought out by true conflict.
What follows is a rough list of the ratios, including where a fighter might be expected to be at each stage of their life.
Novices and enthusiasts. Fighters at ratio 1 are at the start of a serious fighting career. Most are still in school, or have more obligations to attend to than just fighting. Fighting is still a carefree and friendly activity for them. Many fighters who begin their journey as a result of some tragedy start out as ratio 1. Those inheriting a style from a deceased family member, or who are inventing their own style, are also typically ratio 1.
Serious and professional fighters. Many honed and trained fighters are ratio 2. Most professionally trained law enforcement and military personnel are ratio 2. A ratio 2 fighter has typically had to fight in dangerous situations many times and isn't afraid of danger. People without formal training but who are natural geniuses at fighting typically start out at lower ratio 2, but can be higher within ratio 2 with training. Those willing to sacrifice certain things and devote themselves entirely to their art, such as in the case of those with extreme and oftentimes dark ambitions, will also be at ratio 2.
Leaders and old masters. Many fighters in ratio 3 have grown beyond professional fighting and have begun a journey of ambition: to lead others. Highly talented fighters with wellsprings of natural power, ratio 3 fighters typically have begun to become strong enough to gather people to them, whether it takes the form of a school of students, a gang of kids, a cult of personality, or a unit of soldiers, and have begun to instruct and guide them. They are gang leaders and masters of their own arts. Many aging masters who were once more serious and greater ratio often settle at ratio 4 for their twilight years.
Champions. Fighters in ratio 4 are on a different level than what most normal people would ascribe. Typically, ratio 4 fighters are the champions of fighting, and tend to dominate the top tiers of whatever tournament they elect to participate in. They are some of the toughest foot soldiers available to even the most hardened criminal organizations. Ratio 4 fighters have struggled through a long hard life to get to where they are--with many near death experiences, and usually have only survived by the consent and influence of other fighters much, much stronger than this.
Grandmasters. At this ratio, a fighter has persisted beyond all odds. They have attained and actively maintain grandmaster status in their art. At this point, a fighter who has attained this level of strength is able to redefine what is possible for practitioners of their art. A ratio 5 fighter is usually part of an organization: If they aren't the leader of their organization, they are certainly one of its strongest lieutenants, serving underneath a much greater power. They have usually made great sacrifices for their arts, either having been created by or lost something to some of the strongest powers on earth.
Beyond human. There are only a handful of people in the entire world who have achieved this level of mastery. Oftentimes, they sit at the helms of vast world-spanning empires built up solely to enable them to become the strongest. The people who are ratio 6 have often reached near or total perfection in their art, and have cast aside any and all pretenses of being human. A lot of the time, this level of power comes at the cost of many other countless lives, so it is hardly a path for the meek. Any ratio beyond this is unquantifiable--it is the realm of figurative and literal gods.