Every playable unit has a set selection of up to 3 jobs that they may choose from. A unit may only have a single job active, dictating its basic attack, primary ability and attributes. However, the abilities from a unit's jobs may be equipped, allowing a level of customization.
What is a Job?
A job provides a collection of skills to a unit. Every job comes with a set of main skills, a set of basic/sub skills, a reactive and at least one passive. Each job is standardized across all units that have that job, but there are some unique jobs only available to a specific unit and there are job upgrades available for many jobs. See List of jobs for summaries of most of the available jobs. When the job is selected as the currently active job, the unit also receives the stat benefits from the equipment applied to raise the job levels of that job (all job mastery bonuses will be available regardless of the active job).
All units come by default with their first job (commonly referred to as J1). To access additional jobs you must apply limit breaks to the unit. It takes 5 limit breaks to access the second job (J2) and 15 limit breaks to access the third job (J3). Note that not all units have a third job available (notably protagonists - some of which can acquire them via a quest later).
Once you have the appropriate number of limit breaks to access a job, you must unlock it using 6 of the appropriate job tokens for that job. Clicking on the job token slot will show you where you can obtain that particular job token from event quests (these can be done in single or multiplayer version). Alternatively you can buy job tokens from shops, although the stock of tokens changes regularly. Note that some collaboration unit specific job tokens are only available during the relevant collaboration event (such as the caster tokens for Fate Yomi), but you can use wildcard job tokens to replace them. Wildcard job tokens can't be used for job upgrades, only base jobs.
Upgrading Job Levels
Once you have unlocked a job, you can upgrade the job levels of that job by applying equipment. Each job level requires 6 specific pieces of equipment to upgrade to the next job level. Most of the equipment is generic and is used by multiple jobs, but the first equipment slot for job levels 9 to 11 of a unit is a job-specific item that is only used by that job. Note that for collaboration units, they often have at least one job which is limited to the collaboration, and those job-specific items are typically only available to be acquired during the collaboration. If you do not obtain these before the collaboration is over, you won't be able to maximize the unit unless you use Omnicrystal Equipment Diagram Pieces to replace the job-specific items. These are only available in limited quantities from occasional sources such as bundles or celebration shops.
When you raise your units to job level 11, then fill all the equipment slots at that level, the job is considered mastered. When you master a job you get a % bonus to a few specific stats (the stats that it benefits vary by job). The job mastery bonus not only applies to the currently active job, but to all jobs on the unit, regardless of which one is currently active. So to fully maximize a unit you may want to master all of their jobs.
Once you have raised a unit's job level to 11, you may wish to enhance the job level 11 equipment items for additional stats. This will only impact the unit when they are using that job as their main job, so it is not useful to enhance equipment for jobs on the unit that are only used for extra stats or abilities.
Once you have access to more than one job on a unit, you will want to configure their abilities. You can change the active job on a unit in the unit screen by clicking on the job, then clicking the "Job Change" button. The currently active job is flagged as "Set". You can then click on "Ability Setup" to adjust which abilities are enabled for that job. There are 5 slots available to configure:
- Main Ability: This is locked to the currently active job and provides a set of primary skills that the unit can use
- Basic Ability (Sub): This can be changed to the basic ability set provided by any job unlocked on the unit and provides a set of secondary skills that the unit can use
- Reactive Ability: This is an ability that is used in reaction to when the unit is attacked. Each job provides one reactive ability (with a purple icon) and you can choose from all the reactive abilities you have unlocked on the unit. Some abilities such as Counter Snipe or Absorb Jewels may only activate when attacked by a basic attack, whereas others may apply to all attacks, such as Reflection or Stance of the Inheritor
- Passive Ability (2 slots): This is an ability that provides additional benefits to the unit. Each job typically provides 1-2 passive abilities (with a green icon) and you can choose from any that you have unlocked on the unit to fill your 2 passive ability slots
Note that some units also have a job+ or enchanted job upgrade available. Both types of upgrade require that you have 15 limit breaks and have reached job 11 on the job that the upgrade replaces (i.e. sniper for Caris, bard for Polin). To upgrade to a job+ on a unit typically requires special tokens and equipment that are only available during a limited time event. For enchanted job upgrades, the tokens and equipment are permanently available. When you upgrade, the new job fully will replace the job it upgrades (including the job mastery, so there is no reason to master the old job before upgrading). You should never do the job upgrade until you are sure you have acquired all the necessary materials to fully master the job, especially in the case of job+, because those materials will not be available again until the event is rerun, which can take a long time.
In some cases a unit may have a 2nd level job upgrade, known as a J++ (for a job+ upgrade to a job+) or a JE+ (for a job+ upgrade to an enchanted job). To access the 2nd level upgrade, you must first upgrade to the first level, then job level that to at least job level 11, at which point you can apply the 2nd level upgrade. 2nd level job upgrades start at job level 11, so you won't need to raise the other job levels a 3rd time, just apply the items specific to that job upgrade to master it.
See Job Upgrades for a list of all currently available upgrades.