The King's Beast, Volume 9 (The King's Beast #32-35)

After years of pursuing vengeance, Rangetsu has finally found news of her brother, and he’s alive! But Sogetsu is locked up in the inner palace, where his very flesh is being harvested as medicine for an emperor obsessed with immortality. And now that the emperor has his hands on both twins and their mysterious powers, he’s never going to let them go...