Impact Brothers

The Impact Brothers, known as the "Three Pile Brothers" (杭打ち三兄弟) in Japan, are three pile driver robots that can combine to form Impact Man. In Mega Man 11, the Impact Brothers appear as obstacles in four parts of Impact Man's stage before they combine to fight as Impact Man in the boss room. Before they appear, a beam of light shows the direction they will come from. They can't be damaged by Mega Man. These enemies appear as rectangular robots, having a single eye on each side of their head and a spike that allows them to impale anyone in their way. They are able to drill through solid material on their way.

Kui-ichiro
Kui-ichiro (クイイチロー) is the oldest of the Impact Brothers, colored black. A straight shooter who never fails to drive his point home, Kui-ichiro takes control when the three brothers combine to form Impact Man. Kui-ichiro forms the bottom torso, thighs and skull cap of Impact Man.

Kui-jiro
Kui-jiro (クイジロー) is the middle child of the Impact Brothers, colored yellow. Kui-jiro lacks decisiveness and tends to look to his brother Kui-ichiro for instructions. Luckly, those instructions are just "hit things." Kui-jiro forms the left foot, left arm and left pectoral of Impact Man. According to his bio, Impact Man puts himself at great risk being controlled by Kui-jiro, who is stated to be unruly.

Kui-saburo
Kui-saburo (クイサブロー) is the youngest Impact Brother, colored orange, and the most responsible after Kui-ichiro. He always makes time for proper maintenance, so his spike is constantly spotless, shiny, and sharp. Kui-saburo forms the right foot, right arm and right pectoral of Impact Man.

Trivia

 * The Impact Brothers' names are prefixed with Kui- (杭) which means "pile," while Ichiro, Jiro and Saburo are masculine Japanese given names meaning "first son," "second son," and "third son" respectively.