On the way to Akumojo Castle, you hit a big storm. The professor discovers that Nadia is playing music on her keyboard to create the clouds and keep you away from Akumojo Castle. If you didn't get Blue Sky March, check the bottom of the Habara page to find out how to get it.
Stop the Music
Put on the Thief costume. On Rizo island, go into the house. Then pick the door in the back and go through.
The turtles here might jump out of their shells when their HP is low. They don't do it right away, so if their HP is low, you might want to just ignore them for a while and see if they hop out of their shells and start walking around. The naked turtles might drop a Golden Mallet. You might also be able to steal a Golden Mallet from them. The turtles in their shells don't have the Golden Mallets. Only the naked ones do. This is the only way to get a Golden Mallet.
When the path goes in a narrow curve at the top, try going south through the wall. You will reach a chest with a Carbon Rod inside. Now you can continue east to the exit.
You'll find Nadia playing her storm music. Don't bother talking to her. She will just push you away. Instead, wait for her to step away from the keyboard, then check on it. You will replace the music with Blue Sky March. (Check the bottom part of the Habara page if you don't have Blue Sky March.)
Nadia will play Blue Sky March, and the clouds around Akumojo will disappear. Return to the ship, and now you can set your SeaNavi to Akumojo again. This time, you will really get there.
Enter the Castle
Once you reach Akumojo Castle, get off the ship and go east until you cross the bridge into the castle.
Follow the path in the castle until you have gone up a staircase that goes left to right. Go through the south wall to get a Long Sword. Then go north until you reach the next room.
When the path splits, go east. Go through the first door, then go through the northeast wall to pick the lock on the chest for a ?-Decal. Return to the hall and go west, then pick the locked gate that has a chest behind it. The chest contains the ~Borscht~ recipe.
Go back to the hallway and continue west. At the end of the hallway, go south to get a Swanky Soup. From there go all the way north to reach a staircase. Go up it and exit the room.
In this new room, go straight up to reach a save room with a bathtub.
From the save room, go out via the south exit. Then go east and follow long path to reach the next room. Head along the hallway and you will encounter a monkey. Go through the door south and west from you to get a Plus Potion. Go back to the hallway and go east. Pick the gate in the south wall to get a Diamond. You can pick the north gate if you want to, but you won't be able to open the chest until you have Lockpicking at level 2.
Instead, continue east along the hallway but don't go down the stairs. If you go through the south door, you will find a chest mimic. It looks like an ordinary chest, but it is an enemy. If you get its HP really low, it will try to run away, and then it will turn into an actual locked chest. Pick the lock and you might get a War Hammer, or gems, or coins.
Fight the Fire Giant
Go back north to the hallway. If you go through the north door, you will have to fight a miniboss. It's a big red giant that breathes fire. If you stand directly in front of it, it won't be able to hit you when it breathes fire. It will be able to hit you with its other attacks, though, and it takes a ton of potions to survive. The giant might drop a Flame Knuckle, usable only by Drivers, when it dies. If you leave and come back to this room, you will have to fight the giant all over again.
At any rate, go down the east stairs. Don't go through the south door unless you want to fight another of those giants. Instead, go through the north door and pick the chest to get a Knockout Club. Now go back to the hallway and continue east, then go through the door to the north to get out of this area.
In the next room, when the path splits, go north. Go up and then through the east wall to reach a chest that contains a Pickaxe. Go back to where the path split, and go south. The next time the path splits, go north to get Herbs, then go back to the split and go to the east. Skip the rooms along the way and just go up the stairs to the exit.
Now you can save the game. There's no bath tub, but you don't need to heal up. Just go north. Some things will happen in the next room. You will need to tap Terry a couple of times at one point. Also, at one point, you will get to see the Professor and Mochi's Japanese names on the Professor's screen again!
When you're back in control, there's a bathtub to the east that you won't need right now because you automatically were healed up. You can go south to save the game if you wish.
Head back to the room with the bathtub. If you go through the center door, you will have to fight another fire giant. Instead, go west and through the door here.
When the path splits, don't bother going east. It just takes you to the balcony where Bull and Nadia were.
Instead, go north at the split and through the door. You will go across a bridge. In the next room, the path is straightforward until you reach the end of the stairs. Go past the first south door, and instead go through the second south door to get a Plus Potion. Then if you want, you can fight the chest to the north. It's another mimic chest. If you make its HP really low, then you might get a Viking Sword when it runs away and turns into a normal chest.
Now go back toward the west, and go through the second south door (the one you passed earlier.) After going down the stairs, go through the first north door you encounter. Go up through the hallway, then go to the southeast of the room, where there is a table and chairs close to the wall. Walk south through the table to reach a hidden room where you get Blue Eyes v. 5. Now head back north and go to the northern part of the room, where a blond guy is hanging out. Check the bookshelf on the right to learn more about the Professor and gain some Wisdom.
Now go back to the hallway and head west. When the path splits (which it does almost right away), go through the south door to get a Ruby. Return to the small room and go through the upper door on the right and you will reach the exit.
In the next room, when the path splits, go north. Go west past the first door and head through the second one. You will find the ~Croquette~ recipe. Then go back the way you came and go through the first north door that you skipped just a moment ago. Go through the door in the north wall to find another mimic chest. If you make its HP really low, then you might get a Badelaire when it turns into a normal chest.
Go south from there until the path splits again. Go east and south, and get the Sapphire from the chest. Go back the way that you came and go straight north when you can. You will reach a room with a bath and a bed.
After you have healed and saved, exit through the north door. The paths don't have any splits at this point. Eventually you will have to fight another fire giant. You can't avoid this fight. Once that guy is gone, keep going, ignoring the chest if you don't have Lockpicking up to level 2. There will be another chest on the way that is another mimic. You might get a Gaia Hammer from it if you bring its HP down and let it run away.
You will reach another bath and bed room. This is the last opportunity to save before the final boss fight. Be sure to save here, because if you don't, then after you beat the final boss, your save slot won't have any of your progress through Akumojo Castle.
When you're ready, go into the north door.
The first enemy is a dragon. Its HP is 4000 but you just have to reduce it to 2000 in order to get rid of it (temporarily.) After you do, you'll fight Bull Beatnix and Lester Sprawl at the same time. When they're gone, you'll fight the dragon again. After it's gone, you'll fight Mint.
If you want to use your trick decals, be sure to do so either during the Dragon battles or the Lester and Bull battles, because you can't use the decals at all in the Mint fight.
The dragon is pretty easy once you get used to dodging its attacks. If the dragon is floating over the battlefield such that you can see its tail, run sideways away from it. It might swing its tail at you, and its tail is longer than it looks, so if you try running away toward the bottom of the screen, its tail might hit you.
Another attack that it might do if it is floating over the battlefield with its tail visible is to shoot whirlwinds toward the bottom of the screen. When it's shooting whirlwinds, you'll become pinned to the south wall. However, it's easy to avoid the whirlwinds just by running away to the side. You'll know that the dragon is about to shoot whirlwinds if it floats there for a moment without swinging its tail. This gives you plenty of time to run out of the way.
If it flies into the sky, it can send down fire, ice, or lightning. You can dodge the fire and ice if you watch the top screen. If it shoots lightning, stand somewhere that isn't directly below it, because it seems like the lightning shoots near the spot that the dragon is hovering over.
Sometimes, the dragon dips below the rear wall and then floats up and sits there for a moment. When it does this, it's about to shoot fire. But before it does, you have a chance to hit it, so go into battle mode as soon as you see the dragon dip below the rear wall. You will only have time for one or two hits, so be prepared to run away before it spits fire. If it spits fire and it's not near the middle of the screen, you can hide out in the upper corners of the battlefield. Otherwise, if it is near the middle of the screen, hide in the lower corners instead.
Be careful not to get near the dragon when it goes to the back wall unless it dips down below the wall for a moment, because otherwise, if it just sits there, it might grab you instead and drop you onto the battlefield, hurting you.
Lester Sprawl and Bull Beatnix
Once you have reduced the dragon's HP by half, Mint will fly up with it and there will be some dialog. Then Lester and Bull will attack at the same time. Go to a corner of the battlefield such that only one of the two guys can reach you. The little parapet in the bottom-right corner of the screen is a good place.
This is a good time to use your Mochi decal, since it will affect both of them if Mochi is at the proper level to attack all enemies on the screen. In fact, you might want to use all of your battle decals while fighting these two: the Mochi decal, the Balloon Decal, and the Sun/Moon decal.
After you defeat them, the dragon comes back.
Dragon, round 2
When the dragon returns, it has a wider-range fire breathing attack, and after it breathes fire, it will fly directly at you to either grab you or swing its tail at you, so be sure to run away as soon as it's done breathing fire. Its elemental attacks from the sky are stronger as well. For example, its snowflakes fall at an angle instead of straight down.
Otherwise, the dragon is not much harder than it was last time. It just takes patience to defeat it.
When you defeat it, the cell will fall out. First you might want to use your Constellation Decal because you won't be able to use any Trick Decals during the next part. Then use your Cell Decal on the cell and watch what happens.
Then you must fight Mint. It's a pretty straightforward battle. She has a normal attack, an attack that knocks you back, and a star attack that is some kind of magic and might stun you momentarily. The only challenge here is to stay close so you can hit her and to keep your HP up.
Once Mint is defeated, that's it! You won the game! Congratulations! Watch the dialogs and ending scenes, and wait for the game to save. You can watch the rest of the ending, or you can just turn the game off after it saves. If you watch do the whole ending, be sure to wait for a while after it says Fin. Then tap Mochi. Then once the game is just sitting there doing nothing, go ahead and turn off the game or restart it.
That's not all, though. There are plenty of sidequests and other things to do after you beat the game.