X'rphan the White Wyrm (白竜ゼーファン, Hakuryū Zēfan?), commonly known as the Frost Dragon or the White Dragon, was a high-level nocturnal boss, found at the top of the West Mountain on the 55th Floor of Aincrad in Sword Art Online.
The dragon was capable of producing a rare mineral called «Crystallite Ingot», which was formed inside its body and which, according to rumors, could only be obtained by a party with a master smith. However, upon being killed, the dragon dropped only a small quantity of Cor and some poor-quality equipment, which did not even reimburse the cost of the potions and healing crystals used by most parties while fighting the dragon. The mineral itself could actually be found within the dragon's lair as its excrement.
X'rphan was a white winged-dragon with huge jaws and ruby-red eyes. Its body was covered in scale-like crystal shards of ice.
The dragon's attacks included slashes using both claws, a freezing breath attack and a blizzard assault. When the dragon opened its huge jaws and released a hardened sound, it was about to unleash its breath attack in the form of a wave of white gas. When the dragon flew higher than usual and fully extended its wings, it began a blizzard attack by beating its wings forward and causing the snow below it to move. Additionally, due to its ability to fly, players needed to use long-range weapons like halberds or throwing weapons to bring the monster down to ground level.
Kirito and Lisbeth attempted to obtain a Crystallite Ingot from X'rphan to forge a new sword for Kirito, but as Kirito had nearly defeated the creature, Lisbeth came out of hiding too early and got blown away by the dragon. As Lisbeth was about to fall into the dragon's lair, a giant hole in the ground, Kirito jumped in to catch her and prevented her from taking fatal fall damage. As the lair was too deep and slippery to climb out of and had an anti-crystal field, preventing the use of teleportation crystals, the two were forced to spend the night there. After spending the night together, they managed to find the mineral, which turned out to be the dragon's excrement, buried in its lair, much to Lisbeth's disgust.
At that moment, as the dragon was nocturnal, it returned to its nest for the day, but found Kirito and Lisbeth there. After Kirito confused the dragon by running along the wall at a speed faster than the dragon could track, Kirito grabbed the tip of the dragon's tail, triggering the surprised dragon to take flight. Once they were above the pit, Kirito let go of the dragon's tail and the dragon started slowly flying in circles.