As previously stated, Maria's Vitality is crap, which is why your HP gains suck. Rule 1: If you ever want her Vitality to go up, put her in the front row. Rule 2: Bows suck in this game. Give Maria something else, like an staff or knife. Rule 3: Get her better armor. She'll probably get her ass handed to her within five seconds in the Ice Cave if she doesn't have good armor.