Enter the base of the Cult of the Curse Mark, beat people up, and get information.
Eclipse and Nobu were walking through a forest in the Sound when they were ambushed by a group of bandits/thugs. Upon closer inspection (aka interrogation), they seemed to be an organized group. One of them was willing to point out the location of their base, or one of their bases at least, and so Eclipse assembled a group to go investigate these bearers of the curse mark.
Amaya and Nobu met up with Eclipse, then headed into the forest. They went to the designated area, but didn't see anything that looked like a base. As they were looking around, Amaya stepped on some hard ground. She cleared the surface to reveal a hatch, which Nobu blasted open. Then Nobu jumped into the dark pit, with Amaya and Eclipse following. They ended up in a small chamber and headed down a dark hallway, where they encountered others with a wall of iron bars separating them from the residents. Nobu approached, and was then fenced in with another set of bars. Nobu tried to punch through and beat the bars, but the guards attacked forcing him on the defensive. He then was able to blast the ground beneath to allow everyone to crawl under the bars and they were able to defeat the guards through a combination of that and a flash bomb detonated by Eclipse.
They continued down to another room and Nobu blasted the door off. Here there were seven occupants, but one escaped. The three ninja were able to make quick work of their foes and then continued into the next area. Here they encountered many doors, the biggest of which led to more enemies who attacked when Eclipse opened the door. Three opponents waited for them, two of them far more substantial than the previous and well able to make use of the curse mark. A battle ensued and the occupants of the base ended up losing their lives. The facility was then searched and Eclipse turned up some religious-like documents and discovered a name and location - Omuro Neikyou and Mount Pisga.