Yeah, you can get the katana for free from one of chests. Getting the armor for free is trickier though (I won't spoil it), and you're probably better off just buying it yourself so you can use it earlier on. By the time you can get it, you'll probably be rolling in cash anyways.
And the defeating the war god is pretty much the crowning achievement of a fighter/mage, so don't be surprised if you don't beat him right away. Just remember that defense>>>>offense , and make note of what kind of attack he uses, then train accordingly. Once you do manage to beat him though, you'll wonder how he ever gave you any trouble in the first place ("Your silk armor softens the blow! Sylvia takes 1 damage!"

)