The Dorsal Excalibur is a sword traditionally wielded by Echowarrior, inspired by and named after the mythical weapon associated with King Arthur. It has the general length of traditional Japanese longswords, but the design of European blades; its hilt features a curved guard for the hand which resembles a dolphin's dorsal fin and contains a spherical crystal of similar size to a marble. It is composed of an alloy called psionium, a mixture of metals including iron, titanium and lead.
This same weapon has reappeared in other works written by Echowarrior's creator, with varying levels of power. It looks a lot better wielded by a girl.