Mari Straiter is Alto Straiter's sister. She was cursed and turned into a crystal, setting off Alto's journey to the Ivy Tower. She was considered kind, strong-minded, and caring. Alto speaks to her during his journey but it is unclear if she can hear her within her crystalline form.
At a certain point Mari discovered she had the ability to heal without the use of a relic, having that she used it to help the sick and wounded from the attack. with them noticing the relicless magic the villagers took Mari as the Legendary Witch and imprisoned her, using a powerful relic they turned her into a crystal, witnessed by Alto he reacted by grabbing her and running from the village in search for a cure at the Ivy Tower.