The bros have found the three pieces of Fire Ore Toadette needs. She says they won't believe what she can do with it. She sends them ahead and will bring their papercraft to them when it's ready. Go up using the Up button, then go north. Bowser's happy the bros made it here. Paper Bowser thinks they're not worth fighting, when they can fire a Papercraft Bullet Bill. It chases the bros until it's destroyed by a fireball. Another fireball destroys the Papercraft Bill Blaster. Toadette says their papercraft is ready. Bowser's upset at Toadette's tenacity. Paper Bowser orders minions to ready the ultimate papercraft. The bros' new papercraft is Papercraft Fire Mario.
Paper Kamek says their efforts were in vain. They've repaired and upgraded Papercraft Megacrinkle Goomba. Press (X) to throw fireballs. If another papercraft is hit with enough fireballs, it will catch fire and won't be able to move for a while. First up is Papercraft Whomp. He'll fall on the ground, which can stun you. If you're able to dodge, you can use a jump attack. After Papercraft Whomp is defeated a Papercraft Airship will appear. It fires Papercraft Bullet Bills. Use fireballs to bring it to the ground. Be careful not to fall off the edge. Defeat it and Papercraft Megacrinkle Goomba will appear. Once you cross onto its side, the gates will rise back up. It's much faster than before, but dashes shorter distances. Use fireballs to stun it. After you defeat it, a different gate drops. Step on the platform to move to the next area.
Next up is Papercraft Bowser Jr. There's a hole in the floor. He'll use the same attacks as before. After it's defeated, you'll have to dodge flames. Take the platform to the next area. Papercraft King Boo and Papercraft Boos are here. Defeat Papercraft King Boo and a platform will take you to the next area. Papercraft Kamek is here. Its magic prevents you from hitting it with fireballs. Just use jump attacks when it uses its magic. Heal if necessary, charge up, then move onto the next area.
The arena is quiet and empty. It shakes and a door in the floor opens. Papercraft Bowser appears, manned by Bowser and Paper Bowser. Paper Bowser says it will take more than fireballs to defeat them. It will back into the bros to hurt it with its spikes. Jumping on it won't work as it uses its fireproof shell to protect it. After it breathes fire, use your fireballs. Stun Papercraft Bowser, dash into it to knock it over, then jump on it. After a couple of hits, it will do a spin attack. Dodge it, then hit it with fireballs, then jump. It can also jump after a spin attack. After a lot of damage, the Bowsers say they'll regret attacking and their papercraft will not be defeated. It will take a few more hits after this.
Bowser is upset. Paper Bowser says they need to regroup and assemble the Koopalings. The path ahead breaks up and is replaced with spikes.