Blade is his name in the anime. He used to be a burglar during the war along with Sword so that they wouldn't starve. Meta Knight was running away from Wolfwrath when he got blocked by Sword and Blade. When the monster tried to kill him and Sword, Meta Knight had saved them by bringing Wolfwrath down into the water. They had decided to join Meta Knight and help him look for a young Star Warrior who is found out to be Kirby. It is in the episode "Hour of the Wolfwrath" or "Sword and Blade: Loyal and True" that they help defeat Wolfwrath.
It is seen that they do basically whatever Meta Knight does, like watching television, shopping, etc. At one point, he even mentioned that he wanted to be a chef.