Skill

Most Operators in Arknights have skills; strong, triggerable abilities that can aid them or other Operators offensively or defensively by enhancing their stats, modifying their functionality, or giving them new capabilities altogether.

Only 3★ Operators and above have skills; 1★ and 2★ Operators have no skills whatsoever.

• 3★ Operators only have a single skill that is available initially.
• 4★ and 5★ Operators have two skills; the first is available initially and the second is available once they are promoted to Elite 1.
  • An exception to this is Amiya, who has three skills, following the same mechanics as 6★ Operators (see below).
• 6★ Operators have three skills; the first is available initially, the second is available once they are promoted to Elite 1, and the third is available once they are promoted to Elite 2.

Operators with multiple skills can only choose one of them to be used at a given time, which is done from the Operator or squad menu.

Generally, the first skill is a generic skill shared across all Operators of the same class and/or branch, while the second and third skills are unique to each Operator and often act as core to the Operator's playstyle.

Usage

Skills are activated in two different ways, both of which requires it to be charged by having enough Skill Points/SP and have valid target(s) to be present within the skill's range if it requires one:

• Auto skills are immediately activated as soon as they are charged.
  • Some Auto skills requires a condition related to the skill's effect to be met for it to be activated. For instance, most Trapmaster Specialist's skills will only be activated when the count of their respective trap is not at maximum; if the count is topped off, the skill will be charged but not activate until the trap's count is reduced by deploying one.
  • On the same note, Flametail's Quick Intuition and Vigil's Packleader's Gift will not be activated if she/the Wolfpack still has the buff from the previous activation, hence, until Flametail takes a Physical attack (and dodges it) or the Wolfpack attacks an enemy, Quick Intuition/Packleader's Gift will charge but not activate.
• Manual skills are activated on the player's command, by tapping on said skill's icon in the HUD when it is charged.
  • Certain Manual skills also requires a condition related to the skill's effect to be met for it to be activated.
  • On the same note, Push Stroker/Hookmaster Specialists cannot shift enemies with their Manual skill if there are no enemies within their range. If an enemy is blocked behind the Specialist's range, they will be within the latter's attack range, but not skill range. Certain complex stalling strategies actually makes use of this quirk, as activating the skill will interrupt the Operator's attack.
• Passive skills are active at all times with some being context-sensitive.

Few skills can be deactivated by tapping the skill's button on the HUD while the unit is selected and the skill is active, ending it prematurely. Certain skills can only be used a certain amount of times in an operation; once the skill expires after its usage limit is reached, it cannot be charged anymore.

Most skills last for a short duration, but some skills last for an unlimited duration (actually for a sufficiently long period to be functionally unlimited in most cases, see Trivia for details). Despite not being unlimited, skills with instantaneous effects (e.g. Power Strike skills) are treated as if their duration is unlimited.

Some skills, usually Auto ones with instantaneous effects, can store multiple charges; while the skill is immediately usable after it is charged, the Operator can still charge it and stores additional uses of the skill up to a limit.

Special usage

Mechanic	Information
Ammunition	Instead of lasting for a set duration, Ammunition skills lasts for a set number of attacks and can be deactivated at will once activated.
Overcharge	The skill can recover/restore additional SP, up to 2× the normal limit, to have additional effects when activated; all excess SP will be lost when the skill is activated.
Overload	The skill have additional effects while its duration is below 50% the total duration.
Mana	The skill costs Mana instead of SP, which only recovers while the unit is not on the map, and can be activated at all times.
Chanting	The unit must prepare for a while before activating the skill, which stops them from attacking; if the unit is disabled while Chanting, the skill will fail to activate.

Upgrades

All skills start in Level 1 and can be upgraded through 6 additional levels from the Skill Upgrade menu on each Operator's Character Details page. Skill upgrades apply to all of the Operator's skills if they have multiple skills and requires the following:

3★4★5★6★

Level	Skl. Sum.	Material(s)	Requirement(s)
	1	–	–
	2	Few T1 upgrade materials
	1	Few T2 upgrade materials
		Few T3 upgrade materials	Promoted to Elite 1
	2

Level	Skl. Sum.	Material(s)	Requirement(s)
	2	–	–
		Some/few T1 upgrade materials
	3	Some/few T2 upgrade materials
			Promoted to Elite 1
		Some/few T3 upgrade materials
	4

Level	Skl. Sum.	Material(s)	Requirement(s)
	4	–	–
		Some T1 upgrade materials
	6	Some T2 upgrade materials
			Promoted to Elite 1
		Some T3 upgrade materials
	6

Level	Skl. Sum.	Material(s)	Requirement(s)
	5	–	–
		Many T1 upgrade materials
	8	Many T2 upgrade materials
			Promoted to Elite 1
		Many T3 upgrade materials
	8

Specialization

Once the Operator's skills are at Level 7, they can be further improved to three additional levels through the Specialization training function, or colloquially known as Mastery training by the community. Only 4★ Operators and above that have been promoted to Elite 2 can undergo Specialization training.

Specialization training is done at the Training Room of the RIIC. The process takes time to complete (which can be accelerated by assigning certain Operators as trainers), and unlike skill upgrades, are done individually for each skill.

Specialization training requires the following:

4★5★6★

Level	Skl. Sum.	Materials	Time	Requirements
	2	Some/few T4 and T3 upgrade materials	8 hours	Level 1 Training Room
	4	Some T4 upgrade materials	16 hours	Level 2 Training Room
	6	Some/few T5 and T4 upgrade materials	24 hours	Level 3 Training Room

Level	Skl. Sum.	Materials	Time	Requirements
	5	Some T4 and T3 upgrade materials	8 hours	Level 1 Training Room
	6	Many/some T4 upgrade materials	16 hours	Level 2 Training Room
	10	Some T5 and T4 upgrade materials	24 hours	Level 3 Training Room

Level	Skl. Sum.	Materials	Time	Requirements
	8	Many/some T4 and T3 upgrade materials	8 hours	Level 1 Training Room
	12	Many T4 upgrade materials	16 hours	Level 2 Training Room
	15	Many/some T5 and T4 upgrade materials	24 hours	Level 3 Training Room

Tips

Specialization training is very resource and time-consuming, especially for 6★ Operators. Thus it is important to know how significant the boost to the skill will be and whether or not it is worth farming the materials for.

If one wishes to quickly perform Specialization training, the fastest method is as follows, taking advantage of Logos' The Meaning of Words or Irene's Mental Training base skills to reduce training times and significantly reduce the amount of time needed:

• Start Specialization level 1 with the fastest trainer available for that Operator, and train them for around 2 hours and 45 minutes at this accelerated speed (i.e. if the trainer has +50% training speed, then train them for roughly 1 hour and 40 minutes; if the trainer has +75% training speed, then train them for roughly 1 hour and 30 minutes; take into account the innate +5% training speed that all trainers provide).
• Remove that trainer; if done correctly, the Operator should have around 5 hours and 15 minutes left on their training time. Swap in Logos or Irene as the trainer.
  • If the Operator is a Guard or Sniper, use Logos and do not use Irene, as her increased training speed will cause her to be unable to train that Operator for 5 hours, and Mental Training will not be ready; vice versa for Casters and Supporters, for which Irene should be used instead of Logos.
• Start Specialization level 2 with Logos or Irene; if this is done correctly, Logos' The Meaning of Words or Irene's Mental Training will trigger, halving the training time from 16 hours to 8 hours.
• Swap out Logos or Irene, and repeat the same process for Specialization level 2, training with the fastest trainer available for 2 hours and 45 minutes at the accelerated speed, then swapping to Logos/Irene.
• Start Specialization level 3 with Logos or Irene; if this is done correctly, Logos' The Meaning of Words or Irene's Mental Training will trigger again, halving the training time from 24 hours to 12 hours.
• Swap out Logos and Irene, and swap to the fastest trainer available for the rest of Specialization level 3.

If done correctly and with the fastest available training skills, a full Specialization training to level 3 only takes a minimum of around 19 hours- an effective training speed boost of around +150%, much faster than what even the fastest trainers can provide!

Trivia

• 1★ and 2★ Operators have skill activation dialogues, but these went unused due to the obvious fact that they have no skills.
• Skills with unlimited duration are not actually permanent, but has a very long duration of 3600 seconds, or a whole hour. On average, Arknights operations are cleared in 5–8 minutes (10–15 minutes for Annihilation), which is much shorter than the duration and thus unlimited skills rarely, if ever, expire.
  • One of the few instances where it is actually possible for unlimited skills to expire (outside of deliberate stalling) is Research Base Quarantine Zone during Pinch-Out Experimental Operation, where some Test Criterion can give enemies insanely high HP (over 2 million) and high enough defenses that most Operators barely damage them, resulting in the operation taking over an hour.
  • Even if unlimited skills do somehow expire, most of them actually applies the effect to the subject permanently although it does not stack should the skill is activated again aside from certain effects such as the Unit Limit increase from Command Terminal.