Crimson Spell [SuBlime] Vol. 4 (manga)

The key to discovering the secret behind Vald's cursed sword is somewhere in the empire of Zenedoura. With information obtained from Limris - new companion and former Consul of the Empire - Prince Vald decides to head there to see what he can find. Along the way, in order to save a gravely wounded Rulca, he deliberately chooses to turn into his demon self! Vald's uncharacteristic recklessness provokes a tirade from Halvi, who then leaves the group without a word.