- "They speak of abnormalities—of a strange energy that warps time itself. Things that shouldn't exist here are appearing near the gates. Things that shouldn't happen are happening. They call this phenomenon the 'paradox' effect."
- —Serah Farron
Paradox (パラドクス, Paradokusu?) is the term used for an anomaly in the spacetime continuum that causes the events in Final Fantasy XIII-2. Paradoxes are believed to be responsible for the apparent overlapping of different time periods, causing unusual types of monsters to appear and otherwise impossible events to occur. They are also believed to cause people to disappear without a trace; the first being Lightning, right after the events of Final Fantasy XIII.
- See also: Datalog/Paradoxes.
Following the appearance of the gate that appeared in New Bodhum in 3 AF, Time Gates began showing up in a multitude of locations. The research institute, the Academy, gave a name to the anomalies that accompany the arrival of these gates and cause impossible things to happen—they called them 'paradoxes.'
In any location where a paradox is present, people report strange occurrences, such as the sudden appearances of unusual monsters, and odd connections to other times and places.
- See also: Fragment/Quiz Mastery.
- Academy Datafile
With our continuing progress into paradox research, we've come to learn that the future can influence the past. Once events in the future are decided, the past is altered to support that outcome.
For people in the future, the past is like an unopened box. Say, for example, at a certain point in time, someone makes a discovery in a set of ruins and learns a fact about the past. In that instant of understanding, past reality is defined.
But then the question must be asked: who, along the entire span of history, is considered to be 'in the future'?
After the appearance of the Time Gate in New Bodhum 3 AF, more had begun appearing in other locations on Gran Pulse as well as in Cocoon. Along with the gates, paradoxes affected the surrounding areas. Objects, monsters, and in some cases people from different time periods would disappear from their current time and reappear in another. Paradoxes were also known for altering an area's landscape.
In the Bresha Ruins 5 AF, the war machine Atlas appeared within the site, followed by its control device. Despite Serah and Noel resolving the paradox, the ruins in 100 and 300 AF are affected by paradoxes, believed to had been caused by the appearance of Atlas's control device in 5 AF. In Yaschas Massif 10 AF, the appearance of the fal'Cie Fenrir 190 years earlier than its predestined time causes the area surrounding the Paddra Ruins to be darkened by an eternal eclipse.
Resolving the paradox in Oerba 200 AF unlocks an alternate time in Yaschas Massif known as 1X AF, where the eclipse never happened and the memories of the Academy scientists (including Hope and Alyssa) had been altered. In Oerba 200 AF, the desolate village's past and future collided, resulting in the area being sucked into a void. Noel and Serah restore the village by solving multiple Temporal Rifts. In 300 and 400 AF, Oerba continues to be affected by paradoxes, leaving Serah and Noel to go through more Temporal Rifts. In the process, they help Mog recover his lost past memories.
In the Sunleth Waterscape 300 AF, large numbers of Miniflan appear in the area. Most of them merge together and form the monstrous Royal Ripeness that threatens Cocoon's crystal pillar. Noel and Serah travel to both the Coliseum and Archylte Steppe in unknown years, and retrieve the White Hole and Black Hole Fragments causing the flan to appear in Sunleth and Royal Ripeness to grow. With the flan reduced to Mutantomato, they defeat it and save the pillar.
In Augusta Tower 200 AF, the Proto fal'Cie Adam uses a looping paradox to continuously regenerate itself after each time Serah and Noel defeat it in battle. When Serah yells at Hope in the past for Adam's creation, Hope gets her message through the Oracle Drive in 1X AF, and Adam disappears from existence. At 300 AF, a paradox caused by someone from another time period affects the tower, causing Noel and Serah to reset the revolving rooms to their proper positions to resolve it.
After Serah, Mog, and Noel leave Academia 4XX AF, they get separated in the Historia Crux and fall into Caius's trap. This is because of Alyssa betraying them by giving them a booby-trapped artefact that she received from Caius. Her voice can be heard, telling Serah and Noel she will no longer exist because of their actions in correcting the timeline, revealing her nature as a living paradox. In reality, Alyssa died during the Purge but when the timeline was corrupted, she was revived.
It is eventually revealed that it is Caius who is creating the paradoxes across the timeline in order to shape the future toward the one goal he seeks: world destruction.
- Main article: Temporal Rift
To solve an anomaly that distorts a specific area Serah and Noel can enter a Temporal Rift and get rid of the anomaly by solving a puzzle. There are three types of puzzles with at times multiple levels.
- Main article: Paradox Ending
Paradox endings are alternate events in the timeline unlocked by certain actions taken by Noel and Serah, making them "what if" endings in a sense. If they defeat certain enemies without first resolving a paradox or make a different decision towards certain events in the main storyline when given the option, a paradox ending is unlocked.
- Main article: Paradox (Theme)
"Paradox", composed by Naoshi Mizuta, is the second most recurrent theme of the game, behind the Main Theme, "Wishes". Variants of this theme are "Giant's Fist", "The Story So Far...", "Paradigm Shift", "Song of the Farseers", "Oracle Drive", "Eyes of Etro", "Oathbrand", "Yeul's Theme", and "Time's Master". It is also featured in the "Closing Credits".
- The paradox is one of the many story elements of Final Fantasy XIII-2 referenced in the song "Worlds Collide", one of the game's battle themes.
- Although the paradoxes affect only timeline after Cocoon's fall and Serah, Mog, and Noel can visit that timeline, Oerba from the past can be visited (Cocoon in its state before the catastrophe), yet this is a paradox ending and might be a paradox loop of Oerba 200 AF.