Vampire Game, Hakushaku to Yousei Recommendations
Both are to do with someone who is "wanted" and the female protagonist helps them with their search for something (In Vampire Game, it's Phelios' reincarnation, while in Hakushaku to Yousei, it's a legendary sword.) The main difference being that Ishtar wants to help, while Lydia wants to be paid to help. The character developments are well paced and each chapter makes you hunger for more.
The art is also wonderful in both!