Yeonhee

She was called one of the lords when she ended a war so she could sleep quietly and the people from her world thought she was saving them. She traveled to the the otherworld when she learns of the Dark Knights and their power. She makes a deal with Dellons of the Dark Knights even though she doesn't fully trust him. It's likely she has a youthful appearance due to her magic abilities and be able to travel through different worlds.