Reina

Also known as Crimson Reina she is a mage specializing in fire magic. She was born to a travelling merchant and became a hunter at an early age giving her the most practical knowledge and experience amongst the Crimson Vow party members. She has a signature fire spell called Crimson Hellfire. Despite being fifteen years old at the start of the series she is assumed to be a similar age to Mile the youngest member of their group due to her height and appearance which is a source of anger for her. Source: Wikipedia