Niflheim, the Underworld (魔界ニブルヘイム Makai Niburuheimu?), also referred to as the Daemonium, is the world of demons (魔族 mazoku?, "demon tribe") in Tales of Symphonia and Tales of Phantasia. It was previously connected to Aselia when it was a planet devoid of life and mana, but the arrival of the comet Derris-Kharlan 10,000 years prior to the events of Tales of Symphonia brought about the sealing of this connection by Ratatosk; this put an end to the substantial demonic influence in Aselia and gave way to the flourishing of life. The demons seek to reincorporate Aselia to their realm at any cost.
Tales of Symphonia
In Tales of Symphonia, the party is able to see a glimpse of Niflheim in a side quest near the end of the story. It is found within the book using the "Sacred Stone" in the Sybak library; this book is actually sealing away powerful demons. It possesses an Exsphere attached to it that functions as a seal, and its contents are written in angelic language. According to the students of Sybak, cries are heard from that book at night, eventually leading to the creation of the rumor that the book leads to Niflheim. Originally, in Heimdall, the book was scheduled to be burned using the Sacred Stone, but it and the stone went missing after the Tower of Salvation's collapse. The party enters this world with the help of Origin, who warns them of its dark history before allowing them to venture inside it.
Upon entering, the party finds themselves in the "Forbidden Anamnesis", a maze-like dungeon full of tricks and powerful enemies. The book portrays the story of the war of the Underworld. Within it are sealed evils who once vied for the throne of the Underworld: the "Hell Knight" and "Living Armor". If the book is uncontained, demonic creatures would be able to escape, and the world would be transformed into Niflheim. By using the power of the "Sacred Stone", the mana from one's body will turn into a holy flame called "Soulfire", capable of purging the evil that lurks in the Underworld. If that power is used at the deepest part of the Underworld inside the book, the book will be destroyed, along with the spirits that dwell within it.
In the original GameCube version of the game, there are fifteen levels to Niflheim, and three statums for every five levels. Each level contains nine block-like stages that are connected by a series of bridges. After clearing the tenth floor, the party fights the "Hell Knight". After clearing the fifteenth floor, the party finds the "Living Armor" and an altar to burn the "Soulfire" accumulated in order to destroy the book. After defeating the "Living Armor", the party proceeds in destroying the book. However, in the PlayStation 2 version of the game, the "Hell Knight" is encountered earlier at the fifth floor, while the tenth floor is now the home to the shadows of three of the Desian Grand Cardinals: Magnius, Forcystus, and Pronyma. After this battle, the party fights the "Living Armor" on the fifteenth floor, but then they must travel through an additional five levels in order to fully defeat the demons of the book. On the twentieth level, another trio of shadows encounter the party, representing three of the heroes of the Kharlan War: Kratos Aurion, Yuan Ka-Fai, and Mithos Yggdrasill. Upon defeating the shadows, the party can finally destroy the book and seal all of the demons within.
Tales of Symphonia: Dawn of the New World
Niflheim takes a significantly larger role in Tales of Symphonia: Dawn of the New World by being the major threat in the end of the game. The demons of Niflheim made a pact with Richter Abend so that he would be powerful enough to fulfill his desire to defeat Ratatosk, who existed in the shape of Emil Castagnier. If Richter is able to succeed, the demons promised the rebirth of Aster, who was killed by Ratatosk. In turn, Richter would open the door to Niflheim, bringing about the re-connection of Aselia and Niflheim. After Richter is defeated, it is revealed that he never intended to keep his part of the deal. Once the demons had revived Aster, he planned to use the "Sacred Stone" to turn the mana of his body into flames, barring the entrance of the demons.
Another inception of Niflheim occurs at Hima, which is being attacked by monsters. In a skit, Tenebrae senses a faint aura of Niflheim in the village which is attracting monsters. Within the sidequest that explores Alice's history, it is revealed by Decus that the aura is emitted by the remains of a lesser demon who perished in the area. The demon made a pact with Alice in order to gain more power. In return, Alice would have to find the "Forbidden Tome of Demon Lords", the same book which Lloyd Irving and his companions found in Sybak. Since the book was burned, the demon lost contact with his masters and died, freeing Alice of the pact. Decus then destroys the rest of the remains, cleansing the aura of demons from Hima, which causes the monsters to leave and the village to return to normal.
- In Norse mythology, Niflheim is one of the Nine Worlds that is an icy realm with nine frozen rivers.
- At some point in Aselia's timeline, there were four mysterious tribes who ruled the planet, dividing the world into four countries. One of these countries was Niflheim, an icy realm visited by Dio and Mel in Tales of Phantasia: Narikiri Dungeon in order to battle the Summon Spirit "Fen Beast" as part of Norn's trial of their souls. This country has no known relation to the demonic underworld, and the two locations are written differently in Japanese text, although the difference itself is minor. The Niflheim of this unknown time period is written as Nivuruheimu (ニヴルヘイム?), while the demonic realm is written as Niburuheimu (ニブルヘイム?).