From the bottom of my heart, I love Ashikaga Chachamaru!
Nitroplus is working on a sequel to Muramasa. However, I don't think she'd fit in the story she also died in the true ending and I feel that her story is already finished. Narahara Ittetsu and Namaniku ATK are also no longer with Nitroplus so I can't say that I really have a whole lot of faith in the sequel, unlike my evil.