Crystarium system

The Crystarium System (クリスタリウム) is a recurring growth system from the Fabula Nova Crystallis: Final Fantasy subseries. Its most prominent appearance to date was in Final Fantasy XIII where it was the base of stat and ability growth for the entire party.

Final Fantasy XIII
The Crystarium System is the ability and statistics development system for Final Fantasy XIII. Each character has a unique Crystarium similar to the Sphere Grid of Final Fantasy X, although systems do not intersect. The Crystarium is fueled by Crystogen Points (known as Crystal Points in the Japanese version), or CP, which are won after every battle, and are spent to unlock nodes in the Crystarium.

The system allows players to select which bonuses their character gains, rather than automatic level bonuses. Players fill the experience gauge between bonuses themselves, which is analogous to level gauges in previous games, but manually filled to fit the player's preference. Each character's Crystarium originates from their Eidolith (the crystal containing their Eidolon) and branches out in six directions, with one branch corresponding to each role.

In addition to the characters' Eidoliths being unique, the spatial layout of each Crystarium is also different for each character. For example, Snow's six roles extend along perpendicular directions, while Vanille's six roles all extend in approximately the same direction, but diverge before slightly converging again, creating a spherical structure.

Crystarium Stage
Each character's Crystarium growth level corresponds to the progress of the game's story. After fighting certain bosses, the Crystarium levels up, enabling players to advance through the layout and possibly upgrade their stats and learn new abilities, but enhancing stats and learning skills are still dictated by each Role's level. By filling up the experience (CP) gauges between bonuses or abilities, the player is able to choose which abilities to learn or bonuses to receive. The player is limited to the abilities and bonuses within each Crystarium level.

In previous games, characters were given stat bonuses or abilities at set levels, while in the Crystarium, these bonuses or abilities are the player's choice. In addition, the main bonuses players encounter are "Strength," "Magic" and "HP," while stats such as "Defense," "Speed" or "Evade" have been removed as attributes, though remain as special effects that can be augmented with abilities such as "Physical Defense + 5%" or "ATB Speed + 10%."

There are ten stages to the Crystarium and the stage of Crystarium is factored in when calculating the Eidolons' rank. The Eidolons have no Crystaria of their own and neither are their stats tied to the character's (as is with Yuna's Aeons in Final Fantasy X). Instead, the Eidolons' stats are determined by their rank, which is the sum of the summoner's Crystarium stage and the number of roles they have advanced to level 5.

Roles
Paradigms model the Job System of games past while adding some level of customization and restriction. Each character in the field can take on one of six roles in a Paradigm; any combination of three characters' roles constitutes a Paradigm. Paradigms can be changed during battle with a Paradigm Shift; however, what is more important to the Crystarium System are the particular Roles each character can take on. The six Roles are as follows:

Each character starts out with three roles in which they are more proficient. A short way into Chapter 10, each character becomes able to access the other three roles, a feature called "Role Development." These secondary roles can be used once the character learns at least one ability from that role.

In each level the three primary roles a character has, there are occasional branches that contain additional skills and stat increases. Their secondary roles have no branches, being more straight-forward and restricted to fewer skills. In addition, CP costs for the secondary roles' nodes are much higher than those for the primary roles, despite having fewer nodes to activate.

Expanding the Crystarium
The characters' Crystaria expand to the next level after certain bosses are defeated:
 * Stage 1 - Initial extent of Crystaria, as of the start of Chapter 3.
 * Stage 2 - Defeat the Garuda Interceptor at the end of Chapter 3.
 * The Synergist role is unlocked for Sazh, and the Saboteur role is unlocked for Vanille.
 * Stage 3 - Defeat the Dreadnought during Chapter 4.
 * The Medic role is unlocked for Lightning, and the Commando role is unlocked for Sazh.
 * Stage 4 - Defeat the Aster Protoflorian near the end of Chapter 5.
 * Stage 5 - Defeat Enki and Enlil near the end of Chapter 6.
 * Stage 6 - Defeat the Havoc Skytank at the end of Chapter 7.
 * Stage 7 - Defeat Barthandelus at the end of Chapter 9.
 * Stage 8 - Defeat Cid Raines during Chapter 10.
 * Stage 9 - Defeat Barthandelus near the end of Chapter 11.
 * Stage 10 - Defeat Orphan at the end of Chapter 13.

Final Fantasy XIII-2
The Crystarium System returns in Final Fantasy XIII-2 as the stat and ability growth system for Serah and Noel, and the recruitable monsters.

Final Fantasy XIII-2's Crystarium differs from the original in several ways. Now, each character can access any role from the start and there is no cap on the development of the Crystarium at any time. However, the player must purchase role levels at the Crystarium before gaining stat bonuses allocated to that level. The structure of the Crystarium has also changed: there are no longer any tiers and the Crystarium takes the shape of the character's weapon of choice. Monster Crystaria take the shape of the creatures themselves.

There is also a large difference between the Crystarium of main characters and the one of monsters: while Noel and Serah's Crystaria are developed with the returning Crystogen Points, the monsters' Crystaria are developed with items that can be dropped by enemies, found in the field or bought from Chocolina.

Final Fantasy Type-0
In Type-0 the Altocrystarium System is used to level the party's magic abilities through the use of Phantoma. Magic spells can be leveled in several fields, such as power, range, MP cost or speed, which vary depending on the spell itself.