User blog comment:Rainsnowandflowers/Ghirahim vs Impa/@comment-5773940-20140809225555/@comment-25063942-20140810131205

That's the problem with the Metroid series: Ridley is the only other regular character of the series apart from Mother Brain and Dark Samus, and these two have both been confirmed to be Assist Trophies, and every other character in the series has appeared in only one or two games, so they don't represent Metroid a lot.