Alexis is the Z-898 who discovered Aselia's real form as a female. He is described to be quite good looking with blue eyes and red hair. At first, Alexis treated Aselia as a toy, forcing her to dress up to please him, but he gradually fell in love with her. He even made a deal with the Deputy Director (an evil woman) to marry her and gain their freedom to kill the rebellion leader (turned out to be the Kalisten twin brother). He later joined the rebellion and he even captured Felix. He loves Aselia very much but he forced his opinion on her because he is afraid of rejection and has spent his entire life in the lab without experiencing love. There were some touching scenes in which you felt invested emotionally for Alexis, who would rather die without remembering Aselia because his life is meaningless without Aselia. I suppose he learned to be more humane because he loves Aselia and wishes to have a family with her.

Out of gratitude that Alexis loves her, Aselia agreed to Kalisten's suggestion to manipulate his memory and restart his life as a Duke's son. Despite the fact that it was done without Alexis' consent, she wished him happiness with a fresh start in life. The Duke (minister of Emperor Kalisten) appears to be grateful to have a son to nag and he sounds like a caring father.I hope Alexis is happy in his new life as a noble son with a title (something he desired in his entire life) and he will find another female who will love him.

Kalisten is the Emperor's son (Z-999). He is the rebel leader's twin brother and he is very handsome with red eyes and black hair. He is initially perplexed about his sexuality because he frequently sees Aselia in her actual female form, which Aselia dismisses as hallucination. To save Aselia, he braves another maze (some sort of forest lab) filled with failed and cannibalistic experiments with mutated animal forms to save Aselia. When Aselia was burned by fire and she transformed into a female, he reawakened his power. However, he misunderstood that Aselia was dead and he roamed the desert for a year inside a lab (some sort of controlled lab with a desert). Aselia was rescued by Felix, who brainwashed her into believing she was his fiancee. Once she regained her memory with Kalisten, she rejected Felix and joined the rebellion. In the midst of struggle, she sacrificed herself to save Kalisten. Afterward, Kalisten was crowned Emperor. During his lonely rule, he waited for Aselia to awaken after THREE YEARS IN COMA. He waited for her to awaken because he adores her. Kalisten is a ML you want to root for, and his story ends happily with him marrying Aselia and starting a family.

Felix is A-888 and Z-987. He is a Duke's son with green eyes and silver hair. He is the step brother of Selina. Behind his attractive feature, he is actually a sad*st who controlled Selina since he fall in love with her as a child. As Felix's step sister, she captured Felix's attention with her beauty (platinum blonde hair and dreamy purple eyes) and innocence. FYI, Selina's mother is Felix's father mistress and he is quite similiar to his father who is deeply obsessed with Selina's mother.

Selina and Felix are not related by blood. As a reader, it made me felt uncomfortable whenever he called her his beloved sister and he caressed her blonde hair. Felix is very obsessed with Selina, and I believe he has sexually harassed her. At one point, Felix mu*dered her mother and his own father in order to possess her. She can't take it anymore and manages to obtain a necklace that allows her to transform into a male form to hide in an all male science lab. She changed her name to Aselia after she lost her memory.

Felix was able to re-capture her after she had been burned by fire and save her life with the assistance of the Deputy Director. With his power as the Duke, he brainwashed her into thinking she was his fiancee. Aselia is in love with him and is planning their wedding with Felix. He treated her better for a year, but he kept her under control with mind-control medicine. His fate is unknown after Alexis captured and imprisoned him in the dungeon. This is my understanding of his ending because it is difficult to mtl the novel from Korean hangul into English words using Google.