The first thing you want to do is rush to the torch. Unless you have a fire guardian spirit, only use living weapon to save your life. You will loose your important fire buff. It's very good to use the huge torch. It will buff your weapon for a very long time, almost the whole fight and the damage boost is so superior to mere talismans. A fast weapon that hits a lot is great. The water guardian spirit is good here because water resist. Don't bother using a guardian spirit to attack, the giant torches are better. It will telegraph it's one hit move by leaning back a little. By the second phase, you should keep moving sideways. Dodge its forward slam or leap, and you have an opening. It's important to keep your cool here. It has huge hp, so you need to be defensive and read it.