Excalibur

is the transformation of Caliburn, created by merging with the three other Sacred Swords; Arondight, Galatine and Laevatein. Essentially an algamation of all the Sacred Swords, Excalibur is the most powerful magical item within the world of Camelot, and as well the original and greatest of all the Sacred Swords. Caliburn's transformation to Excalibur was caused due to Sonic's willpower. His "never give up" attitude rekindled the long lost light of Excalibur, and they were both empowered. Using the Sacred Swords, Caliburn transformed into Excalibur and Sonic transformed into Excalibur Sonic to fight the Dark Queen, Merlina the Wizard's powered up form.

Physical Appearance
Of all the Sacred Swords, Excalibur resembles mostly Caliburn's base form, now with more features however. He gains a crown-like figure on his pulled back hilt with ruby in the center, and a glowing outer blade around his physical blade.

History
Long ago, Excalibur was originally guarded by Nimue, the Lady of the Lake, along with its scabbard. The sword itself rested in the lake in Deep Woods where it was held up by fairy magic. One day, however, a young King Arthur, the ruler of Camelot and England, came to the lake to seek out a new sword to replace his broken one. Nimue decided to bestow both Excalibur and its scabbard to Arthur, because he had proven himself worthy of character to wield them. Excalibur eventually became King Arthur's personal sword, and he used it to save the kingdom countless times. However, Arthur apparently never chose to wield it in public, or at least never in front of the Knights of the Round Table.

Over time, however, the magical power from Excalibur's scabbard that which bestowed King Arthur with immortality ended up corrupting the once noble king, turning him into an evil tyrant who intended to enslave his own people. Eventually, King Arthur's evil began to transform even Excalibur, presumably causing the light of Excalibur to fade away, splitting it into the Sacred Swords Arondight, Galatine, Laevatein and Caliburn. In the stead of Excalibur, an illusion of Excalibur was forged from King Arthur's essence; Deathcalibur. With Excalibur gone, the records and stories about the sword itself faded into legend.

In Sonic and the Black Knight, as Sonic confronted the Dark Queen in the Dark Hollow, it became clear he was no match aganst Merlina's enhanced form and the Scabbard of Excalibur, as he got pummeled to an inch of his life and got Caliburn cut in half. However, even as the Knights of the Round Table told him that he did not stand a chance aganst the Dark Queen and urged him to escape, Sonic refused to run away and tried to continue the fight with a broken Caliburn, but his efforts was still in vain. As the knights questioned Sonic's reason for continuing, Sonic stated with fierce determination and resolve that his only reason for this was that he would not let Merlina get away with this and he had to stop her. With Sonic's determination shinning brighter than ever, the lost light of Excalibur was reawakened within the Sacred Swords. Seeing the event at hand, Nimue had the Knights of the Round Table send the other Sacred Swords to Sonic and Caliburn. The power of the four Sacred Swords combined with the duo, causing Sonic to transform into Excalibur Sonic and caused not only Caliburn to be repaired, but also to transform into the true Excalibur, thus restoring the legendary sword.

Now reborn, Excalibur and Excalibur Sonic engaged the Dark Queen in battle, with Excalibur giving Sonic the means to counter the Dark Queen's magic. The duo eventually got the Dark Queen on the ropes and finally triumphed over her when Excalibur Sonic pierced her with Excalibur. After the battle, Excalibur revered back to Caliburn, which led to Excalibur being lost again for the time being.

Memorable Quotes

 * "Can't you get in close somehow? We'd have a good chance to win if you could close the gap!"
 * "Listen carefully. Timing is everything! Swing your sword at exactly the right moment."
 * "You must wait for your chance to close in for the kill."
 * "Now, go all out with Soul Surge."
 * "You'll never get anywhere like this. Go full force with the Soul Surge!"
 * "Don't underestimate Excalibur reborn."
 * "I am going to teach you the error of your ways!"
 * "Everything must have it's end and we will be yours!"
 * "Foolish wizard! You're willing to sacrifice countless others just to escape your own sorrow?!"
 * "Hmph! You are mistaken if you think this is the limit of Excalibur's power!"
 * "Do you honestly think such a world would function properly?"
 * "She appears to be worn down, we might be able to get through to her now."
 * "There is nothing Excalibur can't cut through!"

Trivia

 * On the hilt of Excalibur, the rubied hilt now resembles a crown, as well as the Black Knight's helmet. This is a reference to how Excalibur is the legendary sword of King Arthur, and Sonic just so happens to be the King Arthur of the game.
 * The power of Excalibur's Scabbard are similar to the real Arthurean Legends, except in the legends, the Scabbard would prevent any wound from bleeding or prevent death from a mortal wound. In the game, the Scabbard only prevents all wounds.
 * The glowing aura of Excalibur has a similar design to the Gran Faust and Divine Avenger from Spiral Knights.
 * The blade of Excalibur is golden in the game; however, it is pure white in its artwork.