She is the Holy school's martial arts instructor and sister of Chiaia. Unlike her serious sister, Mexiah indulges in her hedonistic nature and is shockingly affectionate toward Kenshi or even other girls. It is Mexiah who discovers that Kenshi is easily infulenced by hypnosis, which she uses to turn Kenshi into a massaging machine. Mexiah walks around in little clothing often, thinks nothing of it, and even sleeps with multiple female students at once. Mexiah is able to sense quickly that Kenshi is far superior to her in swordsmanship, and therefore doesn't need to take sword classes, as no one in the Holy land is of a close enough level to him to teach him anything. It is later discovered that she is not Chiaia's real sister, but was discovered by Chiaia's father in the same ruin in which the Seikishin was found. Mexiah's inner form is Doll, one of the three man-made seikishi made to destroy Gaia. After Doll re-emerges to fight Kenshi, she is unable to hurt him because of Mexiah's memories of him. Doll becomes influenced by Mexiah's experiences and feelings for Kenshi, causing her to express new emotions.
Chiaia and Mexiah's father, Naua is also in charge of the Barrier workshop and Wahanly's teacher. Many years before the story starts, Naua finds a capsule which contained Mexiah, and though Naua always knew about her inner form, Doll, he decided to raise her as his own daughter. When the Swan arrives at the barrier workshop to pick up Kenshi's upgraded sekijin, Naua tells everyone about the senshi civilization, Gaia, and the man-made seikishi, as well a device he made which can erase the data within a core crystal. Just after he receives data on a physical examination he had Kenshi take, the Barrier workshop is attacked by Ran's bandits, and he's consequently captured by Doll before he can tell the others about he discovered. It is assumed that he discovered that Kenshi was the child of a man-made seikishi, which he then told to Doll.
The Pope of the church and Lithia's grandfather. As leader of the church, he is privy to much information about the sekishin and the senshi civilization. After Kenshi is revealed as a seikishi, Gen recognizes that Kenshi must remain unfettered by the church in order move and react to Gaia's shield more quickly. Even after the church's headquarters is destroyed by Doll, gen continues to work with the Holy Land's Principal to organize resources in taking back the Holy Land. After seeing the change in his granddaughter Lithia's emotions and attitude, he comes to see Kenshi as a very good person for bringing out those changes in her.
She is Rudeus' older cousin and also his student. When Rudeus was around seven years old, he taught her magic along with math and reading. She is a violent, strong tomboy and merciless towards anyone who holds negative emotions and intentions against Rudeus. When Eris left Rudeus after their first time together, she left her panties and stole a pair of Rudeus' underwear. The current whereabouts of her panties is not known. She leaves him in order to train in the ways of the sword in order to defeat Orsted and eventually reaches Sword King rank. Due to her abrupt disappearance, Rudeus misunderstood her intentions and thought she left him because she didn't like him, thus was the cause for his erectile dysfunction. She is Rudeus' third wife and gives birth to their son Ars and daughter Christina. She is one of the three goddesses Rudeus worships in his religion. A wooden sword that serves as a relic for the Goddess of War is enshrined in the basement. She dies after collapsing and Rudeus not being fast enough to apply healing magic on her (Source: Mushoku Tensei Wikia)
Frederica is a maid working for Roswaal L. Mathers and a member of the Emilia Camp. (Source: Re:Zero Wikia)