Link - https://www.asianfanfics.com/story/view/1202685/a-boy-with-the-red-hair

Jimin is a normal herbalist citizen in the Kingdom of Ulsan with one rare unique feature; his beautiful red hair. 

Prince Suga wanted a new concubine and Jimin was the perfect candidate.

Refusing he decided to run away escaping to the Kingdom of Busan. On his journey, he met a guy named Jungkook and his two aides; Taehyung and Hoseok.