In Arknights and Arknights: Endfield, playable characters (known as Operators) in gameplay serve in one of nine classes: Caster, Defender, Guard, Medic, Sniper, Specialist, Supporter, Vanguard, Striker. Each of the eight classes serve a certain aspect in a mission — and each class consists of various branches (or subclasses) that make more varying changes to the innate abilities of the general version of the class (Core Caster versus Blast Caster).

With the name being a pastiche of pool #16998, the Fate series - Servant Class Tribute pool's title, this pool comprises images containing at least two Operators (make sure that they are officially revealed as playable first) who belong to the same class. Operators in an image that belong to a class branch (or subclass) can be included here if the user comments in the post in question of which one they belong to, for clarification if one is unfamiliar to Arknights' class branch (subclass) system, or if the post's commentary provides the same context. Cosplays are acceptable as long as they represent the same class.