-Since you will not have your brush techniques at first, simply continue to attack Yami while watching out for his saw blade attack. He will also smash holes in the ground. Watch out for them until you acquire the Rejuvenation brush. You can now fill in the holes. Eventually you will obtain the Power Slash brush. You can use your weapon (preferably the Tundra Beads, Thunder Edge or Solar Flare) and Power Slash. When Yami lets his guard down, attack him. You will soon acquire the Bloom brush. Just use Bloom on him to reveal his controller, and attack it. Continue this to defeat Yami.
-Yami's second form is a ball that bursts into flames and chases you around at first. When Yami is not a fireball, attack him. To hit it easier, place a Rosary weapon as your sub weapon with a Reflector as your main weapon. You will acquire the Cherry Bomb Brush. Draw a cherry bomb to blow Yami into pieces, then attack the controller. Later, you will get the Waterspout Brush. Use this to draw water from the fountain to Yami when it is on fire. Eventually you will get the Crescent Brush, which you can use to summon Susano and slice Yami in half. Then, you can attack the controller.