Masaru shook his head. “Oh no. Wa Jin Sen Ryu is a fighting style where you invoke a god to use you as their tool in battle. That’s what we are, and what you’re training to do here. Possession is an entirely different matter. That’s done against the will of the person they take over. The possessed is enslaved to the demon who has commandeered their body, and they have no say in what the demon says or does. That was what they were convinced your father was. An unwilling host to an inhuman evil.”

“Why?”

“Because of the sword he carried. Zangetsu.”

Moon slayer? That didn’t make any sense. Most samurai named their swords.

Unless . . . “Was it a yōkai?”

“They thought it was. Zangetsu had a long, bloody history before your father claimed it in battle. You know how most blades are brittle and break?”

“Of course.” It was why most samurai carried two, and why they relied on their bows and spears more than their swords.

Masaru paused before he spoke again. “Men have wielded Zangetsu in thousands of battles.”

Ryuichi’s eyes widened. Surely Masaru was joking. “How?” No sword had ever lasted so long.

“The stories claim it was forged by the sword god Takemikazuchi.”

“Seriously?”

Masura inclined his head to him. “One and the same. Even better, they say it was a sword Takemikazuchi used when he came down to the Middle Country to subjugate the kunitsukami.”

Ryuichi sucked his breath in. Takemikazuchi had been intent on dominating the terrestrial gods. It’d been a bloodbath, or so the stories claimed. “Do you believe that?”

“I don’t know. Whatever its origins, Zangetsu has powers. There’s no denying that.” He poured himself a cup of tea. “Do I think it possessed your father?” He shrugged. “Doubtful.”

“Then what did?”

“His shadow.” Masaru’s white eyes held an eerie glint. “My theory is that your father’s guilt consumed him so much that it enabled his shadow to take over. That it was able to swallow his decency until nothing remained.”

Ryuichi shook his head. He didn’t buy that. “Not possible. Light destroys the shadows.”

“No, Ryuichi. It doesn’t.” Masaru’s tone sent a chill down his spine. “You need light in order to see the shadow. To reveal it. But it’s always there, whether you see it or not.”

That made the hairs on the back of his neck stand up. “But what of total darkness? There’s no shadow then.”

Masaru let out a deep, insidious laugh. “Fear the darkness, little one. There, your shadow has no anchor. That’s when it can do the most harm.”

That made his stomach sink with dread. “How do you defeat a shadow, then?”

“You can’t. All you can do is control it . . . and pray it never controls you.”

CHAPTER NINE

Ryuichi knew that Keiko had demanded he stay in his room, but he couldn’t.