Operators can unlock two to three Skills depending on their rarity, all of which can reach level 7 through the Skill Upgrade section in the Operator menu. But if you want to further enhance your Operators’ potential, you can raise their Skill Mastery through Specialization training.

Skill Mastery Requirements

You can raise the Skill Mastery for any Operator whose Skills are level 7.

  • Three-star Operators—minimum Elite 1 to raise their Skills to level 5 and aboveFour, five, and six-star Operators—minimum Elite 1 to raise their Skills to level 6 and above

Because two-star Operators don’t have any Skills, they naturally can’t undergo Skill Mastery training. Meanwhile, six-star Operators and Amiya gain a third Skill at Elite 2, so it’s a good idea to promote them first to help you decide on a more cost-efficient Mastery prioritization plan.

Training Room

Operators can upgrade their Skills beyond level 7 through the Training Room at the Base. This room is located at B305—under the Office. You can only raise an Operator’s Skills to Mastery 1 (M1) with a Level 1 Training Room. Having a Level 2 Training Room will increase the limit to M2, and Level 3 to M3.

The building requirements are as follows:

Raising Skill Mastery

Unlike leveling Skills up from 1 to 7, wherein the level upgrade applies to all Skills, Operators can only Specialize in training one Skill at a time in the Training Room. As you need to spend two to three times the amount of resources to max out all Skills, it’s best to be selective about what Skills to M3.

To raise Skill Mastery, simply head to the Training Room and select which Skill to raise. Doing so will unlock M1. Do it twice more to unlock M2 and M3. The cost differs, but you generally need to spend Skill Summary - 3 and some T3 to T5 materials.

It takes a few hours to complete training:

  • M1—8 hoursM2—16 hoursM3—24 hours

Assigning a Trainer can speed up the training time by 30% to 60%—but only Operators with Expert α and Expert β Skills that match the Trainee’s Class will provide this bonus. While your Operators are training, they can still be deployed in battle.

Don’t forget to head back to the Training Room to unlock the Skill Mastery after the training period is over!

Check out How to recover Deployment Points (DP) in Arknights here on Pro Game Guides to help you deploy Operators faster in battle.