Historia Crux The Historia Crux is a gameplay and story element in " Final Fantasy XIII - 2 " . The Historia Crux is the crossroads of the timeline that allows players to travel between locations and visit them in different time periods . The ability to use the Historia Crux , or the power to travel through time , is a power that originates from the goddess Etro . Though the future of the world can be visited via the Historia Crux , the events before or during " Final Fantasy XIII " cannot be revisited , as these events took place before the paradox es began . In " Lightning Returns : Final Fantasy XIII " , the portal which serves as a gate between the Ark and Nova Chrysalia uses a monochromatic version of Historia Crux in cutscenes where Lightning is traveling between the two locations . Datalog . " The Historia Crux is the crossroads between the Time Gate s . It is a separate dimension connecting one age to the next . " " This surreal plane is said to be the border of the chaotic realm of Valhalla , and only those with an affinity for the power of chaos are able to use it to travel through time . Even the godlike fal ' Cie are not free to enter the Historia Crux as they please . " Gameplay . To unlock new places and time periods , the player needs to find artefacts scattered throughout time . Visiting areas at different times will give players access to new items , new monsters , and new sidequests , and can change the course of the game in the form of paradox ending s . With gate seals , any gate in the Historia Crux can be closed , resetting the storyline of that area ; the player still keeps their current party , level , and items . Closing gates allows a fully powered team to fight any previous bosses with more of an advantage . Fighting earlier bosses with the Paradox Scope active can trigger paradox endings . The date system is marked by the letters " AF " , which stand for " After the Fall " . Visitable years range from 3 to 700 AF . In each location and time , there are a certain number of fragment s , with 160 in total , and the number of fragments the player has obtained from each area is displayed in the Historia Crux menu . Years containing X , such as 1X AF , indicate an alternate timeline created by solving paradoxes . There are also places marked with year unknown , such as " Serendipity - Year Unknown - " . All places originally marked with - Year XXX - ( - XXX年 - ) in the Japanese version are changed to - ? ? ? AF - in the English versions . In the Japanese version , when traveling to the places of - Year XXX - and - Year Unknown - , " AFXXX " and " AF ? ? ? " are displayed on the traveling screens respectively , while in the English versions , " ? ? ? AF " are displayed for both - ? ? ? AF - and - Year Unknown - places . Story . In the aftermath of the events that took place in " Final Fantasy XIII " , Lightning is captured by darkness from another world and dragged to the edge of time , thus written out of history . She falls through the Historia Crux , and is transported to Valhalla . In a distant future where mankind is on the brink of extinction , Noel Kreiss , the last remaining human in the world , prays to Etro for a miracle . A portal opens for him and Noel enters Valhalla . He travels through the Historia Crux to find Serah Farron , Lightning ' s sister , upon Lightning ' s request , and together they set out on a journey to save the future by using the Historia Crux to visit different eras to solve the time paradoxes . Upon leaving Academia 4XX AF through a Time Gate opened by a booby - trapped artefact , part of the Historia Crux is damaged and hits Mog , nearly throwing him out of the system . Serah rushes to help him and is separated from Noel ; although the two leave through different exits , they both end up in the Void Beyond . After Caius Ballad is defeated and the Heart of Chaos within him is destroyed , the Time Gates close sealing access to the Historia Crux . It is unknown what happens to the Historia Crux in the end , as the chaos of the Unseen Realm invades the Mortal Realm and the world is turned into Nova Chrysalia . Development . The director of " Final Fantasy XIII - 2 " , Motomu Toriyama , has said there are a few reasons of why the developers included time travel in the story ; they wanted to tell the story of the rebuilding of the world after Cocoon ' s fall , and thematically felt time travel was a good fit for this story . Square Enix received a lot of feedback regarding the linear gameplay of " Final Fantasy XIII " , and with " Final Fantasy XIII - 2 " the developers wanted to incorporate a new gameplay system with the Historia Crux to let the player advance through different areas within the world seamlessly . Voice . The narrator of the summaries in the Historia Crux is by Michiko Neya in the Japanese version and by Anna Vocino in the English version . Musical themes . The Historia Crux has its eponymous leitmotif , titled " Historia Crux " , composed by Mitsuto Suzuki and performed by ORIGA . Suzuki created this theme with the concept of developing a song with multiple tunes mixing into one to capture a sense of time travel . Suzuki completed the basic structure of the song in two days and afterward added the vocals , recorded the drums and violin , and spent time on the process of arrangement . Each time he received new footage from the team he would brush up the song . The song uses irregular time signature because Suzuki wasn ' t concerned about the beats , creating a rhythm that purely relies on the composer ' s intuition rather than logic . Suzuki remarks it must ' ve been tough for the drummer . The theme " The Void Beyond " is a variant of " Historia Crux " , and is used during the segments the characters are lost within time and most locations are inaccessible . A prototype version of " Historia Crux " on the " " titled , " Travelogue _ GuideVocalDemo " features vocals performed by a male artist . Other appearances . " Theatrhythm Final Fantasy Curtain Call " . The Historia Crux appears as the background for the Field Music Sequence of its eponymous theme . Etymology . " Historia " is Latin for " history " , while Latin " crux " means " to intercept at a central point " — in other words , " to cross " .