Libra is a unique ability in the game, available to both Noctis and Ignis. It allows you to "scan" an enemy, giving you information about the health points of the foe, as well as its weaknesses. The latter is, quite obviously, the most important aspect of this skill - thanks to that you will know what types of weapons/spells are going to be effective/ineffective against specific enemies or, what you will stumble upon when dealing with end-game monsters, what attacks will heal them.
First things first, Libra is not available from the start. To be able to use it, you have to change the combat type from Active to Wait - details on that can be found in "Combat types - Active and Wait" chapter. Once you've done that, all you need to do is to stop moving your character. This will freeze the flow of time. Afterwards, you have to select (with the analog stick) the enemy you are interested in and hold the R1/RB (PS4/Xone) button. A circle located in the middle of the screen will gradually fill - this process is what Libra is. Once the scanning process is over, a new window will appear in the upper left corner of the screen, with all the information about the scanned enemy.
Once the scanning is complete, you will be given information about the name of the enemy, its health points and resistances. Resistances are divided into 11 categories and those are (from left to right): Swords, Greatswords, Polearms, Daggers, Firearms, Shields, Machinery, Fire, Ice, Lightning and Light.
Resistances can have 4 different colors and those will tell you whether the enemy is vulnerable, resistant or will absorb (healing itself) the damage from a given weapon type. The colors are as follows:
- Black tint - the enemy will receive normal damage from a specific weapon type or element.
- Orange tint - the enemy will receive increased damage from a specific weapon type or element.
- Violet tint - the enemy will receive decreased damage from a specific weapon type or element.
- Black tint with arrows - the enemy will absorb damage from a specific weapon type or element. It means that the enemy will be healed instead of getting damaged.
You should also remember about a number of things:
- Some of the enemies will be invulnerable to the effects of Libra - mostly bosses. In that case the option to scan will be blocked.
- Noctis and Ignis are the only characters that have access to this ability.
- Ignis can use the ability once you unlock the Analyze skill from the Teamwork Ascension tree. This allows him to scan most of the enemies at the beginning of an encounter - the effect is the same as when the ability is used by Noctis.