Side character at best.
She wasn't a driving important force in any of the games, hell the only Human characters I consider Mains are Lan, Mayl, Yai, Dex, Wily, Regal, Chaud, Yuchiro and Barret, because they were IMPORTANT, granted Barret and Regal only appeared in two games, but they still had a driving force in the stories of the games they came from (Save for Team Protoman but that's not really the canon version going by 6.), Ms. Mari, and Haruka were side characters at best, and Higsby's the merchant, not that he's not an important character but he mostly vanished in 2 and 6 and wasn't really a main character except for BN1 and BN5 (Colonel version again) Tell me one damn thing Mari did that was important story wise.