Cain essentially reached the same conclusion Lucia needed without even being told. As the blond swordsman was locked at 3-Moon he couldn't have pre-cognition or foresight abilities. Then how? What pushed him to gather a large enough force to wage a crusade against Ziminar's allies?
Impressed Ertha decided asking would be the quickest way to get an answer. "Arthur, why are you creating an army? I was told you and your men are basically free at this point. Why do you wish to wage a crusade against the demon lords even when you don't have to?"