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Operations, also known as stages, are the gameplay maps of Arknights, essentially where much of the game takes place.


When selecting an operation, its description will be shown, which provides some background information regarding the operation as well as listing any special additions and features in the operation (such as terrain and devices), if there are any. The player can also check the operation's Map, Enemy Intelligence, Rewards, and Story (if available).

  • Map displays the operation's map, which can be useful to plan the player's deployment.
  • Enemy Intelligence displays the enemies that appear in the operation. Each enemy is unknown at first; after the enemy have spawned in the operation, they will be revealed in its Enemy Intelligence once the operation is cleared.
    • Note that the menu does not show the total amount of enemies, so the player have to manually count them.
  • Rewards display the items awarded for clearing the operation, divided into the following:
    • First clear: Will always be awarded when the operation is cleared for the first time, but some also requires the operation to be cleared with a 3-star rating (see below) as well.
    • Regular: The main reward, which actually may not be given when the operation is cleared depending on its drop rate (which can be inconsistent depending on the item) listed below, if not explicitly stating the amount.
      • Guaranteed (100.0% or higher; if higher, more than one copy of the item may be dropped)
      • Common (70.0% ~ 99.9%)
      • Uncommon (40.0% ~ 69.9%)
      • Rare (10.0% ~ 39.9%)
    • Special: The special reward, which has a Very Rare (9.9% or below) drop rate. While certain events are live however, some items will become the special drop of most operations, which will always be given.
    • Extra: The additional reward, which will always be given at random from the listed selection.
  • Story allows the player to view the operation's story, which may not be available in all operations.

Controls and interface


An operation's interface is divided into the following displays, on clockwise order from the top left in the image to the right:

  • Quit: Shows a prompt to quit the operation.
  • Enemy count: The amount of enemies that have been defeated and entered Protection Objectives, and the total amount of enemies. In Annihilation, the amount of defeated enemies will also be shown to the left.
  • Life Point count: The amount of Life Points in the operation.
  • Change speed: Changes the gameplay speed between normal (1×) and double (2×).
  • Pause: Pauses the game.
  • Deployment Point counter: The current amount of DP.
  • Unit Limit: How many units (Operators and most summons) can be deployed in the operation.
  • Deployment list: Shows the units (Operators, summons, and deployable devices) that can be deployed in the operation. Selecting any of the units here who are not waiting for deployment will prompt the player to choose where to deploy the unit and set their facing before deployment (except for some summons and deployables). The player can cancel the unit deployment by dragging outside the facing indicator.
    • When a unit is waiting for deployment, their icon turns red and a countdown showing their remaining redeployment time will be present.

When an Operator, summon, or deployable/static unit is selected, the game will be slowed to half speed (except in Multivariate Cooperation: Defence Protocols and LTTB, and on Auto Deploy) as the corresponding unit's stats are shown including their skill, trait, and talent which are displayed in tabs.

  • Retreat: Retreats the unit.
  • Skill: Activates the unit's skill. When the skill is being charged, its current and total SP are also shown, and how long it takes before the skill is ready are represented by a green meter that fills the icon.
    • Passive skills are not present since they do not require the player's manual input to activate.
    • Automatic skills are present but cannot be interacted with.


An operation will be rated depending on the result:

  • Operation rating 4.png Clearing the operation's Challenge Mode will result in a 4-star rating.
  • Operation rating 3.png Clearing the operation without losing Life Points will result in a 3-star rating.
  • Operation rating 2.png Clearing the operation after losing Life Point(s) will result in a 2-star rating.
  • Operation rating 0.png Failing the operation will result in no rating.

Clearing an operation with a 4-star and 3-star rating for the first time will award one Originite Prime.png Originite Prime. In addition, clearing the operation with a 3-star rating and not using the Support Unit will unlock the Auto Deploy feature for that operation.

Unique mechanics

Mechanic Information
Poison Haze All deployed friendly units on the operation where the Poison Haze is present will lose HP (actually taking True damage) over time.
Hui and Ming Introduced in Who is Real, Ink Spirit enemies start with either the "Hui" (black) or "Ming" (white) attribute, while friendly units receive them while on Marks of Hui and Ming. Units deal/take more damage against/from those whose attribute opposes each other, but deals/takes less damage against/from those whose attribute matches each other.
Sandstorm Introduced in Operation Originium Dust, friendly units caught in the Sandstorm will lose HP (actually taking True damage) and have their redeployment time increased if they are knocked out while inside it, while enemies will have their speed reduced. Dirt Mounds protect the tiles behind them from Sandstorms.
High Tide Introduced in Dossoles Holiday, enemies submerged in a High Tide will have their ASPD and speed reduced, and lose HP (actually taking True damage) over time, while friendly units have their ASPD reduced and receives Corrosion Damage build-up periodically and when attacked.
Visibility Introduced in Near Light, friendly units cannot be deployed on tiles without visibility and enemies inside them will become invisible. Visibility can be provided by deploying Operators close to tiles without visibility and through City Neons and Knight Crests.
Snowfall Introduced in Break the Ice, friendly and enemy units will intermittently be inflicted with Cold while a Snowfall is active. Penetrating Cold Snowfalls also intermittently shift enemies.
Londinium Secondary Defense Artillery Introduced in Episode 10, fires a powerful shell at the friendly unit with the highest block count when fully charged to deal massive True damage to the target and anyone in a large radius centered on the target, even if they are invisible/camouflaged.
Waste Energy Interference Introduced in Lingering Echoes, halves the automatic SP generation rate of all friendly units.
Realigned Flux Introduced in Lingering Echoes, increases the automatic SP generation rate of the friendly unit "linked" with it by 50%, counteracting the Waste Energy Interference penalty. Realigned Fluxes are emitted by Tubas and activated Resonators, and will be forwarded to the direction the linked unit(s) are facing.
Blood Ledger Introduced in Il Siracusano, will be filled up by Blood Debt over time which can be accelerated when most Famiglia enemies and Siracusan Civilians are defeated. Should the Blood Ledger is full, it will trigger Asset Liquidation which buffs enemies until it runs out and spawns a Famiglia (Silent) Cleaner.
Gravity Introduced in Lone Trail, can be manipulated by having an enemy with a weight of 3 or higher or a friendly unit with a block count of 1 or higher on top of one of two Gravity Switches. Friendlies facing towards/against the gravity and enemies moving toward/against the gravity have their ASPD or speed, respectively, increased/decreased.
Planetary Debris Introduced in Lone Trail, can be pushed away by either shifting them, attacking them certain times (but can only be damaged by adjacent friendlies), or manipulating the Gravity, at which the Debris drifts along the opposite direction, damaging enemies it collides with. Also blocks friendly unit deployment and reroutes enemies.
Steam Introduced in So Long, Adele, comes in two types:
  • Carmine Steam, which deals Arts damage and inflicts Burn Damage build-up to friendly units within upon appearing and increases the damage they took, as well as reducing the damage taken by enemies within.
  • Pure White Steam, which increases the damage taken by enemies within and reduces the damage taken by friendly units within.