• Lord Ranmaru’s curse ties his immortality to the sword he used to slay his lord; if it’s ever broken, he’ll age a thousand years in a night.

• Reina’s AI prototype may already be self-aware—and feeding on psychic energy through social media.

• Nobuto Mizuhara’s serum might not grant immortality but transference—moving a soul from one body to another.

• A fourth family, long thought extinct, may be manipulating events from the underworld—descendants of yokai rulers sealed in the Edo period.