You need to defeat a scary monster to get a cute Magical Girl to join your team. This guide will show you how to defeat Nerthus and recruit Mellore in Eiyuden Chronicle: Hundred Heroes.
Eiyuden Chronicle Mellore Recruitment Guide
After Nowa finishes her first job in the game, Ymir tasks her with recruiting more people for the team. The first recruitable person is already in Eltisweiss, your starting city. She is mellore, a little Magical Girl. After telling him where Redthroat Ridge is, he decides to follow her and help her.