Blue Rose Sword

The «Blue Rose Sword» (青薔薇の剣, Aobara no Ken) is a Priority Class 45 «Divine Object» class longsword found in the Mountain Range at the Edge. It is the personal weapon of Eugeo, and was highly coveted by the knights in the Underworld. Its appearance is pure white, in contrast with Kirito's Night Sky Sword, and is inscribed with a blue rose at the center of its guard. It was snapped in half after the fight with Quinella.

Appearance
Blue Rose Sword is a long, white longsword with a ice rose in the middle of guard. There are also ice vines securing the handle and holding a blue gem in the pommel of the sword. The guard itself is floral shaped, and is made out of ice.

History
The sword was created from an eternal block of ice from the «Mountain Range at the Edge», with a single blue rose that had been frozen within it, before it could wilt.

According to Eugeo's vision of the sword's origin, an eternal mass of ice existed at the top of the tallest mountain in the northern mountain range, where the ice never thawed throughout the year. The ice spent tens of years in isolation until a single seed landed nearby. The ice began to melt itself little by little, each day, until the seed became a blue rose. From then on, the ice and the rose talked to each other as friends. However, eventually, the Blue Rose asked to be frozen by the ice, as it could not endure the cold for much longer. And so the eternal mass of ice granted the wish, freezing the rose and itself together, forming into a sword with the rose shut away within it.

At some point, the sword somehow found its way within the White Dragon's cave, where it was guarded by the dragon as it protected the Human Empire, similarly to the three other Guardian Dragons scattered throughout the Empire. According to fairy tales, Bercouli, the founder of Rulid Village, tried to steal it from the white dragon but was caught, though he was later forgiven for the crime. However, when Bercouli became an Integrity Knight, Quinella had ordered him and the Integrity Knights to massacre the Guardian Dragons of the North, East, West, and South, because she could not control them. For unknown reasons, Bercouli did not recover the sword after killing the Northern Dragon.

Alicization Beginning
During Prologue I of Alicization Arc, the sword was found by Eugeo, Kirito, and Alice Zuberg, but, as it was extremely heavy, it was left in the cave.

Four UW years after the events of Prologue I, Eugeo returns to the cave to retrieve the sword and uses his rest days to move the sword from the cave to the storage hut near the Gigas Cedar over the course of 3 months, moving it by several kilometers each time and hiding the sword in the forest at the end of each rest day. Once he successfully transports the sword to the hut, he stores it there with the Dragon Bone Axe. Six UW years after the events of Prologue I, Eugeo shows it to Kirito, who attempts to use the sword to cut down the Gigas Cedar, but fails to do so due to his OC authority being too low at the time to use the sword properly. After the fight with the goblins at the Mountain Range at the Edge, their OC authority reached a level at which they are able to wield the sword properly and use Sword Skills with it, which they use to cut down the Gigas Cedar in several days. Afterwards, it became Eugeo's personal sword with Kirito occasionally borrowing it.

Alicization Running
After Eugeo and Kirito are accepted into the Sword Mastery Academy, Eugeo keeps this sword in the drawer underneath the novice trainee dorm bed, as the Academy rules only allow Academy issued wooden swords for group competitions and practical exams.

Near the end of the first year in the academy, Kirito wants to borrow the sword to be able to show his 4-hit Sword Skills to Sortiliena Serlut, but Eugeo reminds him that his own sword from the Gigas Cedar branch should have been completed by then. After this, Kirito no longer needs to borrow Eugeo's sword, as his own sword's Priority class rivals the Blue Rose Sword.

Alicization Turning
As before, Eugeo is unable to use the sword for group practices and practical exams due to the Academy rules, therefore, the sword is only drawn during its weekly maintenance. However, one day, when Tiese and Ronye are late to come clean their seniors' rooms and Eugeo finds out that Raios Antinous and Humbert Zizek plan to exercise their right as upper-class nobles to punish the girls by raping them, Eugeo uses the sword to stop the upper-class nobles and unintentionally cuts off Humbert's arm.

When they're taken by Alice to the Central Cathedral, Tiese brings the sword to Alice and it's taken with Eugeo to the Cathedral, where the sword is stored in the Cathedral's equipment vault on the 3rd floor.

Alicization Rising
After Cardinal helped Kirito and Eugeo escape the Integrity Knights, she taught them how to use the «Armament Full Control» art for their respective swords. Later, while Kirito was struggling with Fanatio Synthesis Two on the 50th floor of the Central Cathedral, Eugeo used the «Armament Full Control» to trap four integrity knights and Fanatio Synthesis Two.

When Eugeo and Kirito reached the 80th floor, they met Alice Synthesis Thirty and engaged in battle. While Kirito was distracting Alice, Eugeo once again used his «Armament Full Control» art in order to trap Alice to gain some time to use his dagger, however she broke free out of the ice within seconds with the use of her Fragrant Olive Sword.

Alicization Dividing
Eugeo used the sword in his battle against the Integrity Knight Commander, Bercouli Synthesis One. Eugeo attempted to surprise the Knight Commander with «Sonic Leap», but Bercouli repelled him with the «Armament Full Control» art of his Time Piercing Sword. The Knight Commander then let Eugeo complete the first stage of his «Armament Full Control» art, and, once the ritual was ready, Eugeo charged Bercouli with the sword, which Bercouli seemingly shattered. However this was revealed to be Eugeo's plan, as what was destroyed was an icicle, which offered no resistance, allowing Eugeo to keep his momentum and use the skill «Meteor Break», to knock Bercouli into a nearby bath, where Eugeo had thrown the Blue Rose Sword. Upon retrieving it, Eugeo activated the Blue Rose Sword's second, recollection, phase of his «Armament Full Control» art for the first time, freezing them both, and having their Life drained rapidly, causing the the battle to end in a draw.

Soon after, Chief Elder Chudelkin arrived and took Eugeo to Quinella, but left the sword behind. When Kirito and Alice eventually re-entered the cathedral, Kirito recovered the sword and the duo proceeded up to the 99th floor, where they were confronted by Eugeo, who was now an Integrity Knight. Using the «Incarnation Arm», Eugeo recovered his weapon and engaged Kirito in a duel, with both activating «Sonic Leap».

Alicization Uniting
After their duel ended, Eugeo, now freed from Administrator's control, used the Blue Rose Sword's second, releasing phase to freeze Kirito and Alice up to their necks so that he could face Administrator alone. During the confrontation with Administrator, she learned that the Blue Rose Sword was not made of metal and thus could bypass her barrier that protected against metallic weapons. Afterwards, with Administrator having defeated Eugeo, Kirito, and Alice, and left Cardinal near death, Eugeo asked Cardinal to merge himself with the Blue Rose Sword in order to stop Administrator. Cardinal complied, and Eugeo was successfully merged with his sword, becoming a much larger version of the weapon. In this form, Eugeo charged the «Sword Golem», and, after a brief struggle, managed to destroy the golem. He then continued his assault by clashing with Quinella and her «Silver Eternity», but she managed to break the sword-fused Eugeo in half, albeit at the cost of both her weapon and right arm. With the fusion undone, the Blue Rose Sword was left broken in two, while Eugeo was bifurcated.

When Kirito resigned himself to defeat after being overpowered by Quinella, Eugeo encouraged Kirito not to give up, and used Incarnation to repair the Blue Rose Sword with his own blood. With its blade reforged and now dyed a deep red, the newly christened «Red Rose Sword» was given to Kirito, who dual wielded it alongside his Night Sky Sword to defeat Quinella. The sword then returned to its broken state and blue and white coloration.

Trivia

 * In Underworld, roses are miraculous flowers that bear fruit with the most «Sacred Energy» and thus not allowed to be planted by anyone, including civilians, nobles and even emperors.
 * The Blue Rose Sword is thus far the only known Divine Object that was created from two existences and by way of natural causes.
 * The Object ID of the sword is WLSS703.  This ID can be used for certain Sacred Arts rituals, for example, an item locating ritual.
 * In the web novel, the sword's Object ID was DI:WSM:0131.