Warning Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled.

The «Magnatherium» (マグナテリウム, Magunateriumu?) is a rare monster found in the Bear Forest on the 4th Floor of Aincrad in Sword Art Online, and drops high-quality items needed for the Shipwright of Yore quest. The bear spawns near a tree with territorial claw markings.[2]


The Magnatherium has gray hair, each of which is as thick as needles, two red eyes that gleam in the dark, fierce fangs poking from its massive jaws, dagger-like claws protruding from its limbs as burly as logs, a barrel-size but still short and bearlike tail, and black, sharp, gleaming horns on its forehead. The beast is about eight metres tall when it stands on two legs and nearly four metres tall at the shoulder when it stands on all four.[2]

Attack PatternsEdit

When Magnatherium stands up vertically, sucks in air, and a red light flickers deep in the bear's throat, it begins to use fire breath attack, which can be avoided by jumping into a spring or by running between the bear's legs to reach its backside. If there is a long enough distance to its targets, the bears begins advancing on four legs, suddenly lowers its horns and begins charging, following its prey until it either hits a large tree or its targets. After its fire breath attack, the bear stops moving for about twenty-five seconds, and for about fifty seconds after a charge attack. At close range, the bear uses its knifelike claws to attack the player.[2]


Aincrad ArcEdit

Barcarolle of FrothEdit

Having accepted the Shipwright of Yore quest, Kirito and Asuna came to the Bear Forest to gather bear fat for the quest. However, Asuna was determined to acquire the high-quality version of the bear fat, thus they began looking for claw markings to find the king of the bears. Eventually, Kirito noticed on the markings on one of the trees. But just as the two noticed that the markings were eight metres above the ground, the Magnatherium appeared. When the bear stood up vertically, Kirito and Asuna retreated behind a large tree, anticipating a charge attack. However, the bear was actually planning to use a fire breath attack, thus Kirito and Asuna had to jump backwards into a small but deep spring to avoid the attack. After the attack, Kirito suggested to retreat for the time being but Asuna convinced him to at least collect more intel on the monster before doing so.

At that moment, the bear began charging towards them and easily crushed the old tree that Kirito and Asuna hid behind, but the collision stopped its attack and temporarily rendered it immobile. While Kirito considered their next course of action, he noticed that the fallen tree trunk did not disappear, although its roots and branches had shattered like glass. Kirito asked Asuna to investigate and retrieve the trunk, while he lured the bear away. After luring it a safe distance away, Kirito attempted to counter the bear's claw attack with «Slant», but was knocked back by the collision and smashed against a tree.

When Kirito stepped forward, the bear stood up to use another fire breath attack, but Kirito ran beneath the bear to avoid the attack and once he was behind it, he used «Sonic Leap» to attack the bear's tail, which was about three metres above the ground, while it was occupied with the fire breath attack. At that moment, Asuna returned and informed him about the log she investigated. Kirito guessed that the wood would be needed for a later part of the quest, and thus two began repeating their strategy to have the bear charge at large trees to obtain more logs.

When the two no longer had free space in their inventory for more logs, Kirito suggested retreating to town, but Asuna reminded him that they still needed bear fat, and that she would not agree to settle for normal bear fat, thus they had to change their strategy, as the bear still had ninety percent of its hit points. Kirito decided to use Sword Skills to deflect the bear's attacks, while Asuna attacked the bear with single attacks. At the end of the fifty-minute battle, the two managed to defeat the bear.


  • The word "magna" in Magnatherium is derived from the Latin word "magnus" (great), while "therium" is derived from the Greek word "therion" (beast).
  • One of the Magnatherium's weaknesses is its tail.[2]
  • The Magnatherium's charge attacks can be used to chop down large trees to acquire Noblewood Cores, a high-quality version of an item required for the Shipwright of Yore quest, without needing the Lumber skill.[2]