When Julian takes on his final form in the battle after the fight with the sheep and with the clones, the easiest (if not most time consuming) way of defeating him is to stand back at the end of the platform and pound at him with the bow. Recover any HP you lose from his attacks with Wisp (Spirit that gives you the ability to regain health). Also, if you have the Trait Coin for Salamander (Fire, it gives you the PwrUP effect, which gives you a more powerful attack), it will make it quicker and easier. Do not change Spirits. Use only Wisp to regain life and otherwise rely on your weapon. The Pedan Bow can be very effective; forge the Bow with Pedan Stone to obtain it. Dont bother with other weapons, as they will put you too close to him when he attacks, or cannot reach him. Forge and temper the bow to what you think its optimum efficiency is, then shoot away. Also, there is no way to continue the game after you have defeated the final Boss. Complete every quest you can before you start your final adventure.