Hi Fron,
Here are instructions for defeating Riveren:
Boss: Riveren
As soon as the elevator reaches the top, you will see Riveren appear. Throughout the entire final battle, Riveren will be pelting you with Glorbs, so you need to be constantly on the defensive. All you need to do is Gust them away (recommended) or avoid them (not recommended). If you avoid them, they will soon build up and cause you hassle.
At first though, the Glorbs have a more specific purpose. See the thin walls on either side of the area? You need to Vortex a Glorb and smash it through each one.
Once this has been done, you can use a Cyclone to get Toku onto the higher level. Go and stand on the switch and this will open the door below. Direct the King onto the switch down here and this will open the door next to Toku. During this sequence don't forget that Riveren will still be on the attack.
As soon as you have the chance, go through the door. To the right you will see a lit torch. Use it to light the torch that is nearest to Toku. You can now burn down the wooden barrier above.
Use the Cyclone to get onto the floor above and here you will find a Melodia Idol. Now, drop back down to where the King is. Use the fire to burn down the barrier. Head into this room and Riveren will follow you.
Use a Vortex on the King so that he will raise the Melodia head behind. You need to defend him from Riveren's attacks whilst he does this. Once the head has been raised, it will let out the same resonating cry as before. This will scare Riveren away.
Leave the room and Riveren will steal the head of the King! Go up to where you found the Melodia Idol. Gust across to the left and you will find the head. Grab it and take it back to the body. Once the King is complete again, have him stand on the switch to the left.
Take Toku to the platform above and stand on the switch here. Watch out for Riveren's attacks and direct the King back into the main area. Head over to the left and use a Glorb to break the thin wall here.
Do the same as before, use a Cyclone to get Toku onto the higher floor. Stand on the switch here, and then use a Slipstream to burn down the wooden barrier here.
Just to the left is a fruit. Use it to weigh down the same switch that you just stood on. Quickly drop down to the left and stand on the switch here. The way should now be clear for you to bring the King to Toku. With the King here, burn the barrier on the left. You will now be in another area with the huge Melodia head.
Vortex the King and he will raise the head. Protect him from Riveren long enough for the head to let out its cry. Riveren will be scared off again. Stand on the switches to open the doors so that you can send the King back into the main area again. Before following him out, climb as many platforms as you can and you will find the final Melodia Idol. You can now drop back down into the main area.
You will now enter the final phase of the battle. This can be a little difficult to work out. Basically, Riveren will throw a Glorb at you. However, this is a "Super Glorb" that will take a couple of seconds to charge.
When he throws it, you need to run away. You need to do this so that the Glorb is still travelling through the air after Riveren has vanished and reappeared. Once he reappears, Gust the Glorb back at him.
This won't work if the Glorb touches the ground (so it no longer charged) or if you don't hit Riveren in the head. If you hit his body, nothing will happen. After a couple of hits, Riveren will fall to the ground. Run over to him and pull off his mask. This will end the battle and the game!