Dragon Effect: Ryouma Sakamoto Ibun

It's 1867, Kyoto. Ryoma Sakamoto who is a hero at the end of Edo era, had been killed during his secret conversation. However, a mystery group revived him with magic.
The group, actually, is a secret association "Soryu-tai" that Kaishu Katsu directs.
Their mission is to find "Ryuzu" that are scattered all over Japan which make the one who obtains them a great king, taking them back from bad guys and propitiating their power.
The time is limited to a year: this is a story of how a new Edo adventure that revived Ryoma would change history!

source: mangaupdates.com