Information about what Meta Knight looks like when his mask is off in the video games. Spoilers ahead.
Under Meta Knight's mask:
Meta Knight is a swordsman that likes to cover his face under a gray/light blue mask, he clothes himself with a long blue/purple cape and has armor pads placed on his shoulders. He is rarely seen without his mask off.
People who played any of the Kirby games, dueled Meta Knight and beat him surely have witnessed him maskless. After Kirby fights Meta Knight in one on one sword combat, sometimes Meta Knight's mask splits into two and falls off showing his real face. Once his mask falls off, Meta Knight doesn't stay there for long before he grabs his cape, swings it around his body and then disappears from the scene.
The real face of Meta Knight looks very similar to Kirby's, which some fans simply describe him like a blue Kirby. Although his body was first black, these days blue. His body is round with purple feet and pinkish cheeks. When he has his mask on his eyes appear yellow, but when the mask is off they're actually white. Looking at his white gloves, it seems though Meta Knight has hands, but he really doesn't. Like Kirby, he really has short and handless arms.
Below a series of screenshots from Kirby Nightmare in Dreamland of Meta Knight without his mask on and vanishing with his cape.