Yu-Gi-Oh!: The Falsebound Kingdom
Monsters in the Yu-Gi-Oh! universe are not just static creatures--they can change to newer, more powerful forms. A clever duelist with the right card combinations can take a fairly plain deck and, through the fine art of fusion, turn it into an unstoppable force within just a few turns.
To fuse monsters together on the battlefield, you must have a supply of Polymerization, which can be bought from certain traders or can sometimes be found after a successful campaign. One Polymerization takes up one space in a monster's personal inventory. Each Polymerization can be used only once per campaign.
If you create a team with the correct duo or trio of monsters and throw a Polymerization into the mix at the right time, you can smartly extend the round by creating a fearsome monster with a brand-new health bar and a full supply of AP. You had better learn which monsters you can fuse, because the computer-controlled Marshals do not hesitate to use their complete encyclopedia of fusion knowledge.
Here is a complete list of the monsters that can be fused in Falsebound Kingdom. Your first time through the game, you can't collect all the necessary monsters to create all these fusions, but if you continue with the same save file after you've finished the game once, playing through a second or third time, you'll eventually piece together the required monsters.
Skull Dragon: Summoned Skull and Red-Eyes Black Dragon form this fused monster.
Blue-Eyes Ultimate Dragon: Once Kaiba clears the Dragon Lair campaign, the three magnificent Blue-Eyes White Dragons--Azrael, Ibris, and Djibril--can fuse to become this tremendously powerful dragon.
Chimera the Flying Mythical Beast: Gazelle the King of the Mythical Beasts and Berfomet fuse to form this fierce monster.
Cosmo Queen: This powerful combination consists of a Dark Elf and a Mystical Elf.
Crimson Sunbird: You need a Mavelus and a Wing Eagle to create the Crimson Sunbird, a winged supermonster whose attacks cannot be blocked.
Gaia the Dragon Champion: Gaia the Fierce Knight and Curse of Dragons create Gaia the Dragon Champion. The fused monster launches attacks that cannot be dodged.
Gate Guardian: Fuse Kazejin, Suijin, and Sanga of the Thunder to create a huge monster with more AP than all three combined, Meteor B. Dragon: Kaiba collects the Meteor Dragon in the Dragon Lair campaign. Fuse Meteor Dragon with Red-Eyes B. Dragon to form an even stronger monster.
Rabid Horseman: Place a Mythical Horseman and Battle Ox on the same team to create this frighteningly strong fusion monster. Thousand Dragon: The Baby Dragon and Time Wizard aren't exactly the most potent monsters on the battlefield, but their fused form, Thousand Dragon, is a mighty combatant.
Twin-Headed Thunder Dragon: Fuse the Two-Headed King Rex and Thunder Dragon to form this formidable fused Dragon.
Valkyrion the Magna Warrior: You must collect all three Magnet Warriors--Alpha, Beta, and Gamma--to create this fusion, which has very strong attacks.
In addition to fusing monsters, you can use certain items on specific monsters to force them to change into different forms. You can perform these class changes only from the Team Make Up screen, not during the actual campaigns.
Armored Zombie: Zanki becomes this horrific undead soldier when you use Call of the Grave on it.
Dragon Zombie: Use Call of the Grave on the Crawling Dragon to create this undead reptile warrior.
Gaia the Dark Knight: The Black Luster Ritual transforms Gaia the Fierce Knight into this dark form. (Note that this changed Gaia the Dark Knight can no longer fuse with Curse of Dragon.)
Magician of Black Chaos: The Black Luster Ritual turns the Dark Magician into its more powerful form.
Metalzoa: Use Metalmorph on Zoa to create this stronger, slower monster.
Perfectly Ultimate Great Moth: Use the Cocoon of Evolution on a Larvae Moth to create this far more powerful beast.
Red-Eyes Black Metal Dragon: Use Metalmorph on the Red-Eyes B. Dragon to create this metallic dragon.