This was an arbitrary standard scale proposed by Dr Wilfred Millward to help categorise the strength and type of power an anthro exhibits. He proposed it just as superanthros became emergent in the Second Great Auran War.
It puts supers into five separate categories, as follows;
Class 0 An ordinary anthro; no exceptional abilities or ones that could become emergent without rigorous practice.
Class 1 Relatively minor abilities, such as an additional sense, a particularly advanced extant sense or minor increases in strength or resilience.
Class 2 Amalgamated Class 1 abilities or one highly significant ability, such as voice replication or low-level telepathy. Physical constraints often keep abilities in check.
Class 3 Amalgamated significant abilities or powerful and unlimited exceptional abilities, such as long-range telepathy, energy beaming or at least twenty-fold strength.
Class 4 Amalgamated major abilities, e.g. strength and invulnerability, telepathy and forcefields, shape-shifting and the ability to shape-shift others.
Class 5 No known anthro exists at this level, but it is rumoured that some may. If they do exist it is a significant worry, for they may have virtually limitless power.