TRAVELING THROUGH THE MIRROR DIMENSION: Mirror Master can use the Carry ability and may carry up to 5 friendly characters regardless of their speed symbols if they share a keyword with him. If Mirror Master begins his move adjacent to a square of blocking terrain or a wall, his speed value isn't modified by the Carry ability.

So can he carry 5 characters that don't share a keyword with him?

No, the mega-Carry only applies when everyone shares a keyword with Mirror Master. That's how I read it at least.

It is right In the text. The last part only refers to the carry reduction, not th "special flavor" carry rule