Toujou Household
Basara Toujou[]
Basara was originally Zest's enemy. Even though they were enemies, she wanted a master like him which made her wish if her creator (Zolgear) was young, so she could have a relation like that of Basara and his servants. That changed when Zest was saved from her own master after she was declared incompetent. She continued to act cold and call him by full-name basis, but later affirmed that she wanted to serve Basara after he saved her for the second time. Zest is shown to be explicitly loyal to Basara after her contract completion, and she wishes to be useful for him. She also harbors romantic feelings for Basara.
By Volume VII onward, Zest addresses him as Basara-sama. She became among the first girls in the harem to perform oral sex on Basara alongside Kurumi in Voulme VI, and had a pseudo threesome with him and Mio in Volume VIII. She accompanies Basara and company to the hero village in Volume IX.
Mio Naruse[]
Mio was originally Zest's enemy. But after switching sides, Mio and Zest are now allies. The duo participated in a three way pseudo-sex ritual in a store’s hot tub in Volume VIII
Maria Naruse[]
They were originally enemies. However, Zest and Maria are now allies after switching sides.
Zolgear[]
Zolgear was Zest's creator and her original master, she was engineered in a way that Zolgear would never touch her. Zest longed for Zolgear once, until she was cast aside by him as he wasn't pleased that Zest once wondered how things would be if she'd have a different master (which was Basara). As Zolgear's aide, she was known to be strong, fierce, and most loyal to Zolgead amongst the factions.
Shella[]
Shella was Zest's temporary master. Zest has some attachment towards Shella, perhaps out of guilt as she was responsible for Shella's capture which lead to Maria's betrayal. Shella was the one who taught Zest the skills of a maid, which became her new occupation while she was under Shella.