Ninja Duo 3000
Ninja 3000 Katana
Samurai 3000 Katana
Samurai 3000 Tanto
these are all from a scifi/fantasy set called Samurai 3000. they each have sheathes that lock securely to the hilt, and can only be removed by pressing a button/switch
The story behind the set, is that in the year 3000, the samurai have returned. They have used the best of ancient and modern practices to craft the best blades ever. Plasmium Alloy, handforged, razorsharp blades that can cut through anything and withstand anything. or something like that