Throughout their lives, Erik, Alpha and Omega each wielded a katana which they used as a sidearm. Erik and later Alpha wielded a katana called Rache Die Drachen, or "Dragon's Vengeance", whereas Omega wielded a different one named Muramasa (after the legendary sword wielded by the first Shogun of Japan). Ironically, Omega's katana shared its name with an aircraft Omega later flew: the YF-31 Muramasa.
It is unknown how such weapons were crafted, but both Rache Die Drachen and Muramasa are extremely durable. It is likely that their blades could possibly be an early carbon steel-titanium alloy, which would explain the resistance to corrosion as well. They could also deflect bullets if held at the right angle to an incoming bullet, even to the extent of slicing one in half if it strikes the blade head-on. The blades are also non-magnetic, strangely enough, which helps to conceal them more easily (Erik Felsen was known to hide it in his guitar case whenever he went on a commercial flight, as the compartment it was hidden in was lined with lead to block the x-rays at the security checkpoints).
It is also unknown how Erik or his clones obtained such weapons, but it is most likely that Erik's father obtained Rache Die Drachen before giving it to Erik and he to Alpha. There are no indications as to how Omega obtained Muramasa, but knowing his nature he might have stolen it.
In 2050, records surfaced that indicated the possible origins of both swords. Muramase was in fact the Muramasa, a legendary sword forged in the Union of Shirubā; the other, on the other hand, is still debated. It is believed that Muramasa's "sister" blade, Masamune, was originally wielded by a samurai of Shiruba, but that during some of the early contact with the West, said samurai dueled a member of the Knights Sudentor, lost, and had his weapon taken from him, and that the sword was the renamed Rache Die Drachen by the knight (believed to be Sir Erik "Wywyrm" Felsen, ancestor of the Belkan ace of the same name).