MetaKnight has more range than Marth does when they're on the ground. Marth has absolutely no safe move that can out range MetaKnight when they're on the ground, so out spacing MetaKnight there is not going to work. You only out range him in the air, but it's barely. And his aerials are flat out better than yours are. His multiple hit boxes and comparable range and speed makes it so his aerials can and will go right through yours. Marth's fair is good, but it doesn't cover his hurtbox as fast as MetaKnight's does. His will go right through yours.
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