Blade Knight appears in almost every Kirby game as a common enemy, and also in the anime along with Sword Knight. He is mostly colored green, but sometimes colored otherwise.
Blade Knight is one of the most common enemies, giving Kirby the copy abilty Sword.
In Kirby Super Star, and Kirby Super Star Ultra, the ability can be given up and he bocomes a helper. Blade can also be a helper to Meta Knight in Meta Knightmare Ultra.
In the Anime, Blade is a follower of Meta Knight along with Sword Knight. He follows Meta Knight's orders (most of the time) and helps Meta Knight build the Battleship Halberd.
Kirby's Return to Dream Land