Synopsis
The game begins when the Church of Martel goes to war with the Vanguard, and Sylvarant's city of Palmacosta is caught in the crossfire. Countless innocent lives are lost and the city is consumed in flames. This event comes to be known as the "Blood Purge," a massacre allegedly led by the same Lloyd Irving who helped unite the worlds two years before. Emil Castagnier, a Palmacostan boy, is forced to watch as his parents are killed by Lloyd. At the same time, a girl named Marta Lualdi is fleeing the Vanguard with Ratatosk's Core, an orb which contains the essence of the sleeping spirit; cornered by Vanguard soldiers, she appeals to Ratatosk for help, and awakens to see Emil standing over the foes' bodies.
Six months later, Emil now lives in Luin with his aunt and uncle, who abuse him physically and emotionally; he is also bullied by the people of the city, who view Lloyd as a hero due to Lloyd's efforts two years ago to rebuild the town. As a result, Emil is timid, retiring and often unwilling to speak, much less express his true thoughts. However, while investigating local meteorological disturbances, he encounters Marta, who helps him defend himself from some monsters and then flees from her pursuers, both Vanguard and the enigmatic Richter Abend. Richter is a source of confusion to Emil: he speaks brusquely but encourages him to stand up for himself. Richter is attempting to retrieve Ratatosk's Core, which has bonded physically to Marta and is visible only as a glyph on her forehead. Caught between the only two people who have been nice to him in a very long time, Emil decides to help Marta. With the aid of Tenebrae, a Centurion Spirit who serves Ratatosk, Emil pledges himself as a "Knight of Ratatosk," gaining a direct link to the Summon Spirit and a second, hyper-aggressive personality which aids him in battle.
After the three have escaped, Marta explains her plight: she is a former member of the Vanguard, who want to use Ratatosk's power for their own nefarious ends. Ratatosk is also the cause of the weather problems plaguing the world: Tenebrae, as well as seven other Centurions, are supposed to be regulating the flow of mana via the world's monsters, but ever since the Giant Kharlan Tree was destroyed four thousand years ago they have remained dormant. To restore balance to the world's environment, all of them must be awoken from their Cores, Ratatosk last of all; and to strengthen them, Emil must recruit monsters, as recounted above. Emil and Marta pledge to do so, though Emil also has a secondary motive: he wants to find Lloyd Irving, who slew his parents, and get some answers... or at least some vengeance.
As the two travel the world, it becomes clear that neither task will be as easy as it sounds. For one, not only are the Vanguard, led by the sadistic Alice and self-absorbed Decus, attempting to collect the Centurion Cores, but so is Lloyd Irving. For two, the pair frequently run into former party members from Tales of Symphonia, all of whom vouch for Lloyd's character whilst simultaneously befriending Emil and Marta, often lending their prowess as temporary player characters. Emil is left in the uncomfortable position of realizing that his hatred of Lloyd must be misplaced, as his associates are of impeccable character; simultaneously, Lloyd's friends admit that, though they believe in him, his current methods are clearly extreme. For three, Emil continues to encounter Richter, with whom he has a rather confusing relationship; Richter encourages his personal growth, even giving him his catchphrase--"Courage is the magic that turns dreams into reality"—but simultaneously insisting that one day he will attempt to remove Ratatosk's Core from Marta's forehead by lethal force. And finally, Emil must deal with his secondary personality, which he calls "Ratatosk Mode." Ratatosk Mode is brusque, selfish, insensitive and prone to dismiss Marta as an annoyance—which Marta, whose budding attraction to Emil is anything but subtle, does not take very well. Even worse, Ratatosk Mode begins to take over, remaining present even while out of battle and often verbally refusing to relinquish control of his host body.
The first of these mysteries is finally unraveled when Lloyd seizes not just the core of Glacies, Centurion of Ice, but its owner, Seles Wilder, sister of Tethe'allan Chosen Zelos Wilder. Zelos notices that Lloyd is using an especially cloying cologne, which Marta realizes is the same scent Decus uses. Decus has been impersonating Lloyd and is the true perpetrator of at least some of his atrocities. Richter's insistence on defeating Ratatosk begins to unravel when he refers to Emil as "Aster," a name Emil also begins to hear when he visits the college town of Sybak. Aster was a former scholar who began to investigate Ratatosk after the two worlds were combined, with the half-elf scholar Richter by his side. A series of flashbacks reveal that Ratatosk, awakened to the state of the world and the death of the Giant Kharlan Tree which was his to protect, lashed out in anger, slaying Aster without remorse. Richter, furious, swore revenge, despite the fact that Ratatosk now wears Aster's face: when Marta begged Ratatosk for help, he manifested himself as a human, grabbing the nearest body to hand, and creating a fake personality for himself to fill in the gaps, becoming Emil.
The largest complication arises from Richter's agenda. He has traveled to the Ginnungagap, the gate that separates Niflheim, the realm of the demons, from the mortal world, and made a devil's bargain to slay Ratatosk, who sustains the gate with his life, in exchange for Aster's revival. Lloyd has caught wind of this and is gathering up the Centurions' Cores to prevent his success; his unwillingness to explain himself to his friends is characterized as a ploy to protect the new World Tree they planted two years ago. Now aligned in purpose, Emil, Marta and the Tales of Symphonia characters advance to the Ginnungagap to stop Richter from laying all of Tethe'alla and Sylvarant bare to the depredations of demons. Once defeated, though, Richter reviles them for their shortsightedness: he had already made plans to double-cross the demons, using himself as a new barrier, prepared to suffer eternal torment for the sake of his innocent friend. Emil also attempts at this point to display his own self-sacrificial tendencies, trying to goad his friends into slaying him to shore up the demon gate, as well as atone for Ratatosk's murder of Aster. In the end, the gate is re-sealed by the combined efforts of Richter and Lord Ratatosk, but Emil's precise fate depends on the player's choices throughout the game: he may slay himself after wounding Marta through his play-acting; be imprisoned along with Richter; or be released, through the urging of both Tenebrae, Aqua, and Richter, to live out his life with Marta.
