A system typically refers to a team that consists of cards whose active skills synergize to form an infinite cycle in which an active skill effect is present every turn. This can be done with actives that very low cooldowns, but can be also done with actives that have a “haste” effect or a multi-turn effect.
Building a system requires a player to calculate how many turns are needed to loop back to the first active while progressing in a dungeon so that the player knows exactly how many actives are required. Some examples of cards that can form a system are the Reincarnated/Super Reincarnated Chinese Celestials
(excluding Sakuya
), Holiday Sonias
, and Nidhogg
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