Fusion monsters are the original and oldest of the extra deck summons. They were first introduced in 1999 with the release of Flame Swordsman, Charubin the Fire Knight, Darkfire Dragon, Fusionist, and Flame Ghost. Fusions monsters mean just that; taking two or more very specific monster cards and combining them together to make a more powerful monster.

Since then we have been introduced to other extra deck summoning archetypes such as links, syncros, XYZ & pendulums. However fusion monsters are the hardest to summon so you can bet they have an array of overpowered cards that can devastate your opponent. Today we're going to look at 10 of the most powerful fusion monsters in Yu-Gi-Oh Master Duel.

10. Gem Knight Lady Brilliant diamond

This card requires 3 "Gem-Knight" monsters. 

This card effect is as follows: 

• Must first be Fusion Summoned with the above Fusion Materials. 
• You can only Special Summon "Gem-Knight Lady Brilliant Diamond(s)" once per turn. 
• Once per turn: You can send 1 face-up "Gem-Knight" monster you control to the Graveyard, and if you do, Special Summon 1 "Gem-Knight" Fusion Monster from your Extra Deck, ignoring its Summoning conditions. 

This card can pump out your other powerful gem knight fusions with ease which will then trigger their own effect that could easily overwhelm your opponent snowballing them out the game. 

9. Dark Cavalry

This card requires "Dark Magician" + 1 Warrior monster.

This card has the following effect: 

• Gains 100 ATK for each Spell/Trap on the field and in the GYs.
• If this card attacks a Defense Position monster, inflict piercing battle damage. 
• When a card or effect is activated that targets a card on the field (Quick Effect): You can discard 1 card; negate the activation, and if you do, destroy it. 

This card can negate any activation of any card that targets any card on the field during either player's turn with the added bonus of destroying it as well. When you factor in the ATK power this card could gain per spell/trap, this card becomes the best in offense and defense.

8. Destiny Hero Destroyer Phoenix Enforcer 

This card requires 1 level 6 Hero monster and 1 destiny Hero monster. 

This card has the following effect:

• Monsters your opponent controls lose 200 ATK for each "HERO" card in your GY. 
• You can only use each of the next effects of "Destiny HERO - Destroyer Phoenix Enforcer" once per turn. (Quick Effect): You can destroy both 1 card you control and 1 card on the field. 
• If this card is destroyed by battle or card effect: You can activate this effect; Special Summon 1 "Destiny HERO" monster from your GY during the Standby Phase of the next turn. 

This card is able to dwindle your opponent's field and when this card is destroyed to activate its own effect, can special summon itself back to your field during the stand-by phase. Can be used during either player turn.

7. Thunder Dragon Titan

This card can only be summoned two ways. First by fusion summoned using three Thunder Dragon Monsters or special summoning (in place of polymerization) by banishing 1 Thunder Monster from your hand and 1 Thunder fusion monster you control other than Thunder Dragon Titan. 

This card has the following effect: 

• When a Thunder monster's effect is activated in the hand, even during the Damage Step (Quick Effect): You can destroy 1 card on the field. 
• If this card would be destroyed by card effect, you can banish 2 cards from your GY instead.

This card is not only great in  thunder dragon decks, but thunder decks in general as almost all thunder monsters have effects that activate in the hand thus allowing you to destroy your entire opponent's field with little effort. Its effect can also be triggered during either turn including after taking or dealing damage.

6. Dark Magician The Dragon Knight

This card requires 1 Dark Magician + 1 Dragon Monster. 

This card has the following effect: 

• This card's name becomes "Dark Magician" while on the field or in the GY. 
• Your opponent cannot target Spells/Traps you control with card effects also, they cannot be destroyed by your opponent's card effects. 

This card protects your backline from destruction and when paired with the continuous trap "Eternal Soul"  will make this monster unaffected by other card effects, essentially locking down your field and preventing your opponent from countering.

5. MirrorJade the Iceblade Dragon

This card requires a "Fallen of Albaz" monster + 1 Fusion, Synchro, Xyz, or Link Monster.

 This card has the following effect.

• Once per turn (Quick Effect): You can send 1 Fusion Monster from your Extra Deck to the GY that mentions "Fallen of Albaz" as material; banish 1 monster on the field, also this card cannot use this effect next turn. 
• If this Fusion Summoned card in its owner's control leaves the field because of an opponent's card: You can destroy all monsters your opponent controls during the End Phase of this turn.

This can leave your opponent vulnerable by getting rid of all monsters they control and even works on monsters that can't be targeted by card effects.

4. Masquerade The Blazing Dragon

This card requires 1 "Despia" monster + 1 LIGHT or DARK monster. 

This card effect is as follows: 

• While you control this Fusion Summoned card, your opponent must pay 600 LP to activate cards or effects. 
• If your opponent controls a Ritual, Fusion, Synchro, Xyz, or Link Monster, while this card is in your GY (Quick Effect): You can Special Summon this card, but banish it when it leaves the field. 

You can only use this effect of "Masquerade the Blazing Dragon" once per turn.

This card uses your opponent's cards against them as they must pay life points to play any card and activate any effect while this card is face up on the field. This card is perfect at burning and can reduce your opponent's life points to zero very quickly if they're not careful.

3. Lyrilusc Independent Nightingale

This card requires a "Lyrilusc - Assembled Nightingale" + 1 "Lyrilusc" monster. 

This card has the following effect:

• If this card is Fusion Summoned using an Xyz Monster on the field as Fusion Material whose original name includes "Lyrilusc": You can increase this card's Level by the number of Xyz Materials that monster(s) had. 
• This card gains ATK equal to its Level x 500. Unaffected by other cards' effects. 
• Once per turn: You can inflict damage to your opponent equal to this card's Level x 500. 

This deck can become very powerful if summoned the right way and can deal some serious damage since it can also attack the same turn its effect was activated. The added bonus of being unaffected by card effects drastically limits your opponent's options on dealing with a card like this while burning their life points.

2. Dinomorphia Rexterm

This card requires 1 "Dinomorphia" Fusion Monster + 1 "Dinomorphia" monster.

 This card effect is as follows: 

• Your opponent cannot activate the effects of monsters they control that have ATK greater than or equal to your LP. 
• You can only use each of the following effects of "Dinomorphia Rexterm" once per turn. (Quick Effect): You can pay half your LP; the ATK of all monsters your opponent currently controls become equal to your LP, until the end of this turn.
•  If this card is destroyed by battle or card effect: You can Special Summon 1 Level 6 or lower "Dinomorphia" monster from your GY. 

This card is at its most powerful when you have low life points and your opponent has some powerful monsters on the field. You can shut down your opponent's monsters and their attack power leaving them open to being destroyed by this 3000ATK behemoth.

1. Supreme King Dragon Starving Venom

Can be summoned two ways: Fusion summoning using Two dark pendulum monsters or Special summoning by tributing Two dark pendulum monsters on the field. 

This card effect is as follows: 

• Once per turn: You can target 1 other monster on the field or in the GY; until the End Phase, this card's name becomes that monster's original name, and replace this effect with that monster's original effects, 
• Also for the rest of this turn, if your monster attacks a Defense Position monster, inflict piercing battle damage to your opponent. 

This card is the chameleon  of fusion monsters as it can copy any monster effect on either field or in either graveyard. The set-ups for this card is limitless making it probably the most versatile monster in the whole game.

You may also be interested in:

• Yu-Gi-Oh! Master Duel Structure Decks
• Yu-Gi-Oh Master Duel Best Fusion Monsters
• Yu-Gi-Oh Master Duel Best Dark Magician Decks