If you're looking for manga similar to Koihime Musou: Doki Otome darake no Sangokushi Engi, you might like these titles.
The story takes place in a city-state enclosed by the sea. Merchants and adventurers alike gather within the city known as the "world's treasure house". It is a city of endless possibilities and dreams. Here it is that the somewhat odd story of an adventuress and her happy-go-lucky friends unfolds.
A romantic comedy about three guys, part-time worker Chitose Shusuke, the cool, handsome illustrator Otori Kakeru, and the lecherous 35-year-old owner of the bar/cafe where they hang out, Karube Karuo. They flirt with the waitresses, forceful college student Eriko and repeating college entrance examinee Kinako. Soon Chitose will meet a cute young author who is going to become a part of his life...
China: 184 A.D., a time of great turmoil. Zhang Fei stumbles upon a slaughtered village and has a chance encounter that will change his life forever. Guan Yu, second in command of a volunteer army, recruits the brash but inexperienced young Zhang. The army's first duty is to repel an invasion of a walled city, and although Zhang misses most of that action, he has his own. As he saves the life of a little girl, an arrow to the neck throws him off a cliff. He is rescued my two wizards who give him the power to resist all wounds. Zhang is about to become the most powerful soldier in the army, but at a price that could cost him his soul!
The main male character is Asaba Yuma, and the story follows the school life he shares with many girls and his one male friend. These girls include Tsukishima Yuri and her twin sister Hanako, who is in the newspaper club, Yuma's little sister Konami, who likes shogi, and several others. Will Yuma find love in his teenage years?
One day, a weird girl with pink hair and green eyes appears in front of Nagi Tsukuba, an average high schooler. She claims to be Stra, the "Prophecies of Nostradamus" and after guessing his future and guess it, she starts living with him. What will happen with his school life...?
During the Han dynasty in ancient China, three men - Liu Bei, Zhang Fei, and Guan Yu - swear an oath to repair their tumultuous country and become brethren. With their band of volunteers, the three brothers set out for battle, meeting various historical figures from The Romance of the Three Kingdoms on the way. The twist: most of these powerful warriors are female!