S-Class



S-Class threats are those classified by the PRT as among the most dangerous threats in the world.

Requirements
There are multiple ways for parahumans, non-humans or groups to be labeled a class-S threat. High-level duplicators and villains who operate to any exponential degree are automatically considered S-class if their powers generate more instances of power generation or recurring effect in an epidemic pattern. A tinker with the ability to create true AI would apparently be counted as an S-class threat.

Three PRT Thinkers must all rate a situation sufficiently highly before it can be considered an S-class situation.

Response
Being labelled a class-S threat is equivalent to receiving a kill order, in addition to which the PRT calls everyone they can to destroy the threat. According to Miss Militia, the difference in response to a class A crisis and a class S one is minor. Some tertiary protocols change, the Triumvirate are guaranteed to assist, and there are penalties for anyone who subscribed to the critical situation roster if they sit it out.

There were epidemic protocols for dealing with a Class S situation.

One of Dragon's responsibilities was monitoring the known S-class threats for changes or other incidents. She developed a program to predict the patterns of their attacks, which she sent to Armsmaster; using this program, the two were able to predict Leviathan's attack on Brockton Bay and give forces some time to gather beforehand.

Historic Examples
At the beginning of the story, there were six recognized class S threats:
 * Behemoth
 * Leviathan
 * The Simurgh
 * The Slaughterhouse Nine (collectively)
 * Nilbog
 * Sleeper

Other class S threats emerged over the course of the story, including:
 * Echidna
 * Khonsu
 * The Twins (Tohu and Bohu)
 * Scion

Furthermore, Ash Beast had the potential of being an S-class threat but moved slowly enough to be avoidable. Blasto had a "high risk" of becoming S-class. The Number Man referenced the Three Blasphemies as a force on par with Sleeper, the Slaughterhouse Nine, and the Ash Beast, but they were not among the established S-class threats listed in discussion prior to the Echidna incident.

Most threats outside of North America were believed to be destroyed in Gold Morning.

There were threats of a similar level that were not widely known and were dealt with by organizations such as the Thanda. Or contained in PRT Quarantine Sites.

Other class S threads that would appear over the course of Ward include:
 * Machine Army
 * The Tower
 * The Titans

Trivia

 * Wildbow described what S-Class Trickster would look like.
 * The S stands for "Superlative" used to denote something that stands outside a typical rating system that runs from D through to A.
 * While used in real life ranking systems it is most familiar to western readers through Japanese manga and similar.