Roi

Roi grew up with Yatagan, and though both of them were equally powerful sorcerers, she was often overlooked in favor of Yatagan. Though she was a little bitter due to this, she never told Yatagan, and in fact it ended up working in her favor when they discovered Crysmald's secrets. Yatagan had to leave lest her life be in danger, but Roi stayed and was completely overlooked. Even though it would be years until Crysmald was safe again, she never stopped missing her, the only person that ever gave her any attention. So when she learned Yatagan had died, she immediately set out to find a way to revive her. She would spend the next 21 years researching.

In her studies, she became hooked on the idea of making a homunculus that could trick the spell as a soul substitute. That way, she wouldn't have to sacrifice her own life, and she and Yatagan could be alive together again. She experimented with many different recipes, creating many "reject" homunculus and cutting into her own lifespan significantly. At one point, she accidentally let many of them escape. Finally, she created the perfect homunculus substitute, and sacrificed it, successfully reviving her deceased friend 21 years later. 

The experience changed her drastically, and she was all too happy to follow Yatagan on her quest to find her son, if only to be around her again. They did eventually find him in a strange town called Hero Stay Place. While they were staying in the town, she became acquainted with a few of the residents, specifically the older ones. A man named Isoptera asked for the revival spell, and since he was a human and she figured he probably couldn't do it himself, so she offered to help make it happen, instead. So while Yatagan was getting to know her son, Roi prepared Isoptera's spell. Unfortunately, he didn't know how humonculi worked, and became attached to his. All that work for nothing... When she met back up with Yatagan, her friend was devastated, telling her about how her son was a disgrace. Being that their moods were thoroughly ruined, they moved on.

Now, they've moved on from that quest, and are on the hunt for her runaway humonculi, so they can perform the spell and bring back Yatagan's deceased husband. Roi has a suspicion the spell leeches her life away, but if it will make Yatagan happy, she doesn't mind.