The mana lobe (霊力野 reiryoku no / "geeto"?, "spirit power field" / "gate") is an organ found in a person's brain in Tales of Xillia and Tales of Xillia 2. In order for humans to use spirit artes, they must channel their mana as an offering to spirits, an exchange that allows both species to thrive. The mana lobe serves as the conduit of this exchange, as humans draw mana from the organ and communicate with spirits through incantation. The spirits receive the mana, their lifeforce, and apply it to the spell the user wishes to cast through a process known as spirit channeling (精霊術 seireijutsu?).
Long ago, mana lobes served as the sole conduit through which humans were able to utilize spirit artes. However, around 2,000 years prior to the events of the story, the advent of spyrix technology, which allowed for greater technological advancement, began to replace the mana lobe exchange. Humans were no longer providing spirits with mana, and spyrix technology likewise consumed the mana of spirits, killing them. As a result, many humans' mana lobes became atrophied. Maxwell, the Lord of Spirits, saw this problem and sought to rectify it by gathering those who still had healthy, functioning mana lobes and placing them in a world separated from the one plagued by spyrix. He cast a powerful arte known as the schism, which formed an invisible barrier between the two worlds.
The spyrix-infested world, known as Elympios, was left by Maxwell to rot. He felt that those who did not heed his warnings and abused the nature of spirits did not deserve to life, and from this point forward, Elympios experienced a devastating decline as spirits began dying out, thereby resulting in a decline of natural resources. The people who were left in this world no longer had access to their mana lobes' power, forcing the reliance upon spyrix to an even greater extent. The other world, however, came to be known as Rieze Maxia, a utopia in which mana lobes are used to fullest and spyrix ceases to exist until Elympios manages to penetrate the schism, inadvertently hurling a cruise ship through the barrier and stranding an unstated number of Elympions in Rieze Maxia.