Community rulesets

This article details the different unofficial self-imposed challenges and custom rulesets that appear fairly frequently in the community. Of course, these are informal rulesets with no strict authority on adherence to their rules, so this article is merely descriptive of the Arknights community's consensus on these rules rather than prescriptive.

Low Rarity Only

Rarity limitations, such as 4★ or 3★ only are a self-explanatory challenge limitation where operators of a rarity above the one chosen (or even below) are not permitted. They are challenge clears and should be differentiated from guides which use "low-spec" squads to allow a majority of players from being able to follow them without having the gacha units that a higher spec strategy would require.

Low Op Count

Low op count challenges, usually referred to by the number of operators used, are challenge clears with the goal in mind of reducing the number of operators required to clear the map down to the least amount possible.

Intcomp style/No Repeat Operators

No Repeat Operators (NRO) or Intcomp style clears are challenges imitating the rule restriction officially introduced with Interlocking Competition: Hymnoi Wisdom, involving the clear of a wide set of stages (such as an entire event, or even the main story in full) using each operator for only one stage in the run. That is to say, once an operator is used in clearing a stage, they can never be used ever in another stage again. Usually, an operator is considered "used" if they are in the squad of the recorded clear, whether they are actually useful to the clear or not, similar to Interlocking Competition. There are no restrictions on the sequence stages should be cleared in nor amount of times a stage can be attempted — which permits optimizing an operator out of a stage clear to save them for later use. Since keeping a lot of units in store for harder stages is a strategic asset in NRO, most maps tend to be cleared with low op counts.

Tower

Operator Towers (for instance, Platinum Tower, or Magallan Tower) are effectively identical to the NRO challenge, with the added rule that one specific operator is allowed to (and should) be in every squad.

Classknights

"Classknights," or typically known by the class name (i.e. Guardknights, Casterknights, Specknights) restrict the use of operators within a single class or even subclass (such as Summonerknights). This means that all of the operators used in the clear will be part of that class and no other operators are allowed. Some leniency is typically given to that rule in regards to stages such as Annihilation, which effectively forces the player into bringing a Vanguard. The name originates from an early community meme about the Guard class being so overpowered and overrepresented in operator releases that only Guards are required to clear the game, making the game itself Guardknights.

Nicheknights

While technically massively different and distinct from Classknights and effectively allowing operators from different classes, Nicheknights is similar in premise. Nicheknights is a catch-all term for all Operator restrictions based on a specific trait they share. For instance, a Nicheknights clear can include only male operators, or operators of a certain faction, or operators drawn by a certain artist.

1-P Relay

The 1P Relay style involves never deploying more than one operator at a time, making the entire map cleared with only one operator ever deployed at once. This significantly changes which skills and abilities become valuable, and skews team compositions towards quickly available high damage burst and nukes, and away from Medics entirely. Usually, the Deployment Limit is used as an indicator for what is considered "only one operator deployed" which means that the 1P relay ruleset tends to be lenient with the inclusion of Robots, who do not take up deployment slots.

1 Tile Only

One tile only challenges are self-explanatory, the player decides on one tile, and all other tiles are effectively considered banned tiles for the purpose of the challenge. By definition, one tile only is inherently a 1P relay, as using two operators at simultaneously requires using separate tiles. Generally, one tile only clears tend to also not use deployable tokens and objects, such as Interference Mines and Mr. Boom on other tiles than the one authorized.

No Block/Ranged No Ground

No Block is self-explanatory. It is a challenge which involves not blocking a single enemy once. There are two schools to this, which include standard no block, where ground operators who can block are allowed so long as they do not block, and ranged no ground, where effectively no ground operators whatsoever are allowed, limiting the pool to ranged high tile operators.

Speed kills/boss speedrun

This challenge involves killing a boss as fast as possible using burst skills. Generally, time is counted using real time with auto-deploy at ×2 speed. Most commonly, timer starts upon the boss entering the map and technically being "defeatable" — even if some bosses have a hard timer during which they cannot be attacked whatsoever despite being present on the map, such as Faust. Some speed kills generally count map length instead. These are either intended simply for the challenge or to make auto-deploy of certain stages faster and more efficient.