Silver katanas were Kai's main weapons in Seasons 7 to 10. Silver katanas are used very commonly by the ninja, being perhaps the most common variant next to gold. They are prominent in the Ninjago Spinners game, as the Golden Weapons hold more power in the game. Gold katanas are periodically used by the ninja. To date, only Kai still uses a katana as his weapon, using twin katanas and a golden katana later on. Kai, Lloyd, and Nya initially specialized in using katanas. 5.2.2 Season 2: Legacy of the Green Ninja.