The duke of his engagement partner has multiple personalities!? The opening of a harem romantic comedy with one partner! Alma decided to negotiate a match with the duke's family. There is a reason why my engagement partner is a surprisingly good person to talk to! However, the next moment he was proposed, his personality became a "different person". What will happen to this matchmaking!?

Alec, the youngest brother of the renouned Mornort family, has purple hair and purple eyes. His parents were uncomfortable with his coloring, which no human is supposed to be born with, until one day he was banished from the family home. At a loss, Alec happens to meet two girls who seemed like adventurers. At their suggestion, Alec changes the color of his hair and eyes, and enrolls in the Academy of Heroes without telling anyone about his true identity. Alec's life at the academy is a lively one, but there is a secret legend about the color of his hair and eyes that even he doesn't know... (Source: Alphapolis, translated)

Sora was summoned to another world as a hero. While other heroes were bestowed with powerful combat skills, Sora’s skill was something ordinary: “Alchemy.” Ridiculed for having a useless skill, he was exiled to the “Demon Forest.” However, little did they know, his skill was actually an exceptional SSS-Rank skill! Utilizing his alchemy, an unconventional survival journey in another world begins! Source: MU

Hiram, the most powerful demon king in history, ruled over all the demon tribes. He defied the Demon God's demand for sacrifices and lost his life after fierce battle. The demon tribe will never defeat Demon God while living under its control. As long as this was the way of this world, there was no way to become the strongest. Five hundred years have passed since then. Hiram was successfully reincarnated as a "human" youth. Although he was said to be the "weakest", he was actually a human with high potential. To kill the Demon God this time, he began adventurous journey... (Source: Square Enix, translated)

Werner, a brilliant and hardworking magic tool researcher at the Empire’s top institution, the Sage’s Academy, suddenly finds himself expelled by a jealous chancellor looking to profit off of Werner’s inventions. But without Werner, the Academy quickly hits a well, and not a single new magic tool could be developed. It turns out Werner’s theories are way too advanced for anyone else to follow! While the academy flounders, Werner attracts attention from all walks of life—from a maiden dragon to a princess. Armed with the strongest spells and magic tools, he’s ready to enjoy a laid-back life of research...surrounded by cute apprentices to boot! Source: Manga UP!

Based on the Psychic Force Playstation Game. Note: Released in Enix Supercomic Gekijoh Volume 4.

Yoshida, who worked for a black company, died in an accident. Due to a mistake during reincarnation work, he couldn’t be reincarnated in his original world. God suggested him to reincarnate in a different world with a mischievous angel, who unwillingly accompanied him, as his support; and the two were born into the world of sword and magic as twin brother and sister. A few years later, Yoshida took magic lessons from his angel sister and began his special training so that he could lead a fulfilling life. But the younger sister, who changed her mind to enjoying this world, was aiming for a parasitic life where she could live comfortably, so she continued training her brother so that she could use him well. Being an adventurer, or the third generation of inn owners, Yoshida’s second life with a younger sister, who doesn’t wanna work, begins. Source: NU

[Original Webtoon](https://www.comico.jp/comic/997)