Xenovia at first didn't like her at all because she turned into a Devil and still believed in God, and wanted to kill her so she could be forgiven and even called her a "witch", which saddened Asia greatly. Later on, as she found out the truth about her beliefs, she decides to join Rias Gremory's Peerage and becomes very close friends with Asia. Xenovia feels extremely guilty for how she treated Asia at first and constantly apologizes for it, even though Asia has already forgiven her. She, Xenovia and Irina are seen praying together often and make up the "Church Trio" (as Issei puts it) and play eroge games together along with Issei, naked.
Xenovia is very protective of Asia, partially due to the fact that she feels guilty for how she talked to Asia when they met, and takes responsibility for her safety when Issei isn't around. When Asia was thought to have been killed by Shalba Beelzebub, she became enraged. Upon her return, Xenovia wept tears of joy, expressing relief that her precious friend was back.
When she firsts meets Issei, they were hostile towards one another due to Issei being a Devil and Xenovia being a member of the Church, and how coldly Xenovia treated Asia. After she joins Rias' peerage, she attempts to have sex with Issei in order to give birth to strong children as her way of making up time that she feels she lost as a woman while serving the Church. However, due to her lack of common sense from being raised in the Church, she was very blunt with Issei on what she wanted to do with him, and did so while not harboring any romantic feelings for him.
She begins to fall in love with Issei when he expressed his opinions to Michael to provide convenience for her and Asia to be able pray to God without experiencing the pain that came along with it. As the series progresses, it is shown that Xenovia has developed genuine romantic feelings for Issei due to his determination to protect his comrades even if he gets injured by doing so. She frequently tries to seduce Issei whenever she can because she wants to give birth to strong children. She also emits a scary aura whenever the other girls are getting closer to him. She also wants to join his peerage once he becomes a High-class Devil.
Xenovia has been shown to be concerned at times when she feels that she is being left behind in the fight for Issei's love and affection, and will take more aggressive measures to be with him. After Xenovia kisses Issei for the second time, she thanks him for the lifestyle she is currently enjoying, which was only possible due to Issei, resulting in them getting closer.
A good friend of Xenovia. Irina was Xenovia's partner before she was reincarnated into a Devil after learning about the death of God. Irina was disappointed when she found out Xenovia had turned into a Devil but have since made up and stayed good friends. They are rivals for Issei's love, though Xenovia has an advantage, being that since Irina is an Angel she can not actively pursue Issei's affection, meanwhile Xenovia goes to almost extremes to try to be with him. She also enjoys teasing Irina, often calling her a "self-proclaiming angel" or a "self-proclaiming childhood friend."
Rias considers Xenovia a trustworthy servant but she also considers her a love rival since she wants to have Issei's children and does develop feelings for Issei as the series progresses.
Yuuto and Xenovia had a rough start due to Yuuto's hatred towards the Excalibur and the fact that Xenovia was an Excalibur wielder. Xenovia, being an exorcist of the Church, also didn't get along well with the Devils. After Yuuto overcame his hatred on Excalibur and Xenovia learned about the death of the God from the Bible and joined Rias' peerage, Xenovia and Yuuto's relationship improved over time while maintaining their friendly rivalry. However, she still feels inferior to Yuuto's abilities and is determined to catch up to him.
Gasper and Xenovia seem to have a friendly relationship as they are part of Rias' peerage and she has helped train him, though during the training she was seen chasing after him with the Holy Sword, Durandal.
Millicas and Xenovia have shown to get along well with each other, Millicas have shown to admire her for her absolute power in battle and gives her advice on her bad points.
After learning that Diodora purposely set up Asia and his reason for doing so, as well as kidnapping her, Xenovia wanted to take his head and would have if Issei hadn't talked her out of it.
Griselda was Xenovia's swordmaster and legal guardian during her time in the Church. Xenovia is shown to be extremely fearful of her. Upon learning that she has become a devil, she became quite furious on her meeting with Xenovia and started pinching her face. Despite this, she became pleased that Xenovia has changed and she started enjoying her life and asked Issei to take care of her.
Xenovia feels nothing but disgust for Freed due to his violent and heretical ways.