A monstruous dragon that lives in the Blastline, this creature feeds off from the plasma that forms in said place to attack, and is famous for being the main cause of the Platina airships crashing. This monster has also fought with Garzburn over the supremacy of the Dragon's Nest for quite a long time. At the start of Ar tonelico: Melody of Elemia, it was the culprit of Lyner's airship crashing into Viola Forest, and Lyner and his friends had to defeat it later on in order to cross the Blastline and arrive to the top areas of the Tower, in pursuit of the Mir-possessed Shurelia. On the other hand, in the OVA, Slepnir was made into the main villain, which was defeated at the end by Lyner, who was powered-up by both the Harmonics phenomenon and Aurica's Moiskyrie Song Magic.