Heikō Mu.

Despite Susanoo's domination, not all shinobi were willing to accept his chaotic reign. In secret, a group began to form—a gathering of those who still held Heikō's teachings close to their hearts. They were a hidden faction, composed of Heikō's most loyal followers, who called themselves "The Shadows of Mu." Their purpose was not to fight Susanoo directly, for they knew that such a confrontation would end in their destruction. Instead, they preserved Heikō's techniques in secret, training in silence, hiding their rituals from Susanoo's watchful gaze.

The Shadows of Mu moved like whispers, invisible to most, their loyalty unbroken by fear. They honed their skills in clandestine gatherings, preserving the discipline and mastery that Heikō had taught them. Each time they trained, they spoke Heikō's name, ensuring that he would not be forgotten, that his teachings would survive, even in the shadow of Susanoo's tyranny.

Susanoo, however, was no fool. He sensed the resistance, the faint echoes of Heikō's presence that lingered in the shadows. His anger grew, his rage feeding storms that raged through the divine realm. Susanoo summoned his Yōkai—a legion of dark, terrifying creatures—and sent them to hunt down the rebels, to extinguish any trace of Heikō's influence.

The Shadows of Mu were forced to scatter, many of them cut down by the monstrous beings under Susanoo's command. Yet, even in the face of annihilation, their spirits remained unbroken. Those who survived swore an oath to continue Heikō's legacy, passing down his teachings in the most hidden corners of the shinobi world. They became ghosts in the realm of chaos, shadows who refused to let Heikō's memory die.