/Assault Mode

The /Assault Modes, known as /Busters (read as "(Slash) Busters") in the Japanese version, are a series of monsters that are powered-up Effect Monsters versions of already-existing Synchro Monsters, Summoned by using "Assault Mode Activate" on the corresponding Synchro Monsters. Aesthetically, the "/Assault Mode" cards are re-armored counterparts of the original monster.

Statistics
The "/Assault Mode" version has the same name as its counterpart, but with "/Assault Mode" at the end. They have 500 more ATK and DEF, two more levels and a more powerful version of the Synchro Monster's effect (For example "Stardust Dragon/Assault Mode" can be Tributed whenever a Spell/Trap/Monster effect is activated whereas "Stardust Dragon" can only be Tributed to negate a Spell/Trap/Monster Effect that would destroy a card). When the "/Assault Mode" monster is destroyed the regular version may be Special Summoned from the Graveyard.

Evolving Duel! Stardust VS Red Demons
In the anime tour special episode, Evolving Duel! Stardust VS Red Demons, Yusei Fudo and Jack Atlas had a Duel in which they both Summoned "/Assault Modes" of their dragons.

Jack Summoned "Red Dragon Archfiend/Assault Mode" first and began to boast about it but Yusei quickly brought out "Stardust Dragon/Assault Mode". A lot of the Duel consisted of both players using various cards to protect their dragon and take out their opponent's. Eventually, both "/Assault Modes" were destroyed and the regular "Red Dragon Archfiend" and "Stardust Dragon" returned. Yusei increased "Stardust Dragon'" ATK so it could defeat "Red Dragon Archfiend" and used "Synchro Destructor" to take out Jack's remaining Life Points.

Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator
In Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator, Stardust Dragon/Assault Mode and Red Dragon Archfiend/Assault Mode appear as opponents, that can be unlocked by Summoning their card form in a Duel.

The characters Assault Mercenary and Night Wing Sorceress also use "/Assault Mode" Decks.

Support
There are some support cards to "Assault Mode Activate". Those cards help to bring "Assault Mode Activate" to its maximum potential and are powerful cards in their own right, often having high ATK for their Level and helping the user control the field.

Playability
"/Assault Mode" monsters are extremely powerful but in order to be used effectively their user must have very good control over their own deck and be able to summon the desired Synchro Monster with ease. A deck that is too dedicated to the support of "Assault Mode Activate" card may not support the Synchro monster properly enough to be able to summon it quickly. On occasion an Assault Mode monster's effect may not be as desirable as its original version's ("Hyper Psychic Blaster/Assault Mode" does less damage with its effect, generally, than its original version's Piercing Damage, and "Red Dragon Archfiend/Assault Mode" is a double-edged sword with a severe drawback).

Stardust Assault
Because "Stardust Dragon/Assault Mode" has what is considered to be the most powerful effect of any /Assault Mode monster - and because of how easy the original "Stardust Dragon" is to summon, especially with the release of "Starlight Road", - this is the most popular /Assault Mode deck in tournaments. This variant can use many combos to bring out "Stardust Dragon". "Instant Fusion" is very useful in this deck as you can Special Summon a level 5 or 4 Fusion Monster to tune with a level 3 or 4 Tuner. "Destiny Hero - Malicious" is also used with "Emergency Teleport", which can Special Summon the level 8 "Stardust Dragon" with ease: "Emergency Teleport" also combos with "Instant Fusion" if "Psychic Commander" is included in the deck.

Once "Stardust Dragon" is summoned it is important to Special Summon "Stardust Dragon/Assault Mode quickly; thus, "Assault Beast" is used to support "Assault Mode Activate". Once the "Stardust/Assault" is out it is extremely difficult to remove from the field - its effect will negate ATK modifiers, destruction effects and more. The three weaknesses for this card are cards to negate "Stardust Dragon/Assault Mode's" effect, like "Divine Wrath", cards that remove monsters from the graveyard, such as "D.D. Crow", and monsters that have ATK higher than or equal to 3000 without using an effect, such as "Beast Machine King Barbaros Ür".

To speed up this deck you might want to add "Foolish Burial" to send your "Destiny Hero - Malicious" graveyard in order to activate its effect, then summon "Arcane Apprentice". This way you can easily Special Summon "Stardust Dragon" and get an "Assault Mode Activate". In addition, "Sangan" can search your "Arcane Apprentice". "Mystic Tomato" can be useful too as it can summon "Destiny Hero - Malicious" from your deck. Add "Plaguespreader Zombie" to help you return your "Stardust Dragon/Assault Mode" or "Destiny Hero - Malicious" from your hand to your deck.

Monsters

 * Stardust Dragon/Assault Mode
 * Krebons
 * Psychic Commander
 * Eccentric Boy
 * Plaguespreader Zombie
 * Destiny Hero - Malicious
 * Assault Beast
 * Any 5 Level Monsters

Spells

 * Hand Destruction
 * Foolish Burial
 * Upstart Goblin
 * Destiny Draw
 * Instant Fusion

Traps

 * Assault Mode Activate

Spellcaster Assault
To use "Arcanite Magician" and "Arcanite Magician/Assault Mode" in a Spell Counter Deck can be tough but the deck is not impossible and makes for an interesting deck-type to use. "Magical Exemplar" makes Special Summoning much easier and saves time to Synchro Summon your key monster, "Arcanite Magician". "Instant Fusion" works very well with "Magical Exemplar" because you can use it to Special Summon a "Musician King" and use "Exemplar's" effect to Special Summon a "Night's End Sorcerer" from your hand or graveyard. "Arcane Apprentice" is a better choice because you get "Assault Mode Activate" to you hand after you Synchro Summon with it. Also, a very good card to have in this deck is "The Tricky" since he is level 5 and a spellcaster and when used with "Arcane Apprentice", not only will you be able to quickly Special Summon "Arcanite Magician" but his /Assault Mode version as well because of "Arcane Apprentice's" effect.

A very important thing to think about is getting "Arcanite Magician/Assault Mode" out onto your side of the field as quickly as possible. This means getting "Assault Mode Activate" to your hand as soon as possible. "Threatening Roar", "Mirror Force", and "Dimensional Prison" will help keep him on the field so that your efforts will not go to waste.

Another good card to add to your Extra Deck would be "Tempest Magician". Her special effect allows you to add Spell Counters to any monster by discarding any number of cards from your hand. This is a useful way to increase your "Arcanite's" attack and Counters if it runs out.

"Crusader of Endymion" or an "Alchemist of Black Spells" can help "Arcanite Magician" and "Arcanite Magician/Assault Mode" gain ATK and Spell Counters. You can also use "Spell Power Grasp" to put counters on either "Arcanite". Use "Magical Citadel of Endymion" and remove spell counters from it so that your "Arcanite" or "Arcanite/Assault Mode" will not lose ATK when using their effects. Lastly, you can use "Miracle Synchro Fusion". Since /Assault Mode monsters are useless in the graveyard, you can fuse a used-up "Arcanite Magician/Assault Mode" with "Tempest Magician" or "Arcanite Magician" to make "Supreme Arcanite Magician". It's slower than either Arcanite but it is much more powerful and can allow you to draw cards.

Zombie Assault
Creating a deck based around "Doomkaiser Dragon/Assault Mode" has been made more difficult with the limiting of "Plaguespreader Zombie" and "Mezuki" but it is still possible. "Zombie Master" and "Plaguespreader Zombie" can Synchro Summon "Doomkaiser Dragon". Once again, you can utilize the /Assault Mode support mentioned above.

The deck that Doomkaiser Dragon fits best into is one built around "Zombie World", allowing you to Special Summon monsters from either player's graveyard. Possible uses for these monsters include tribute fodder, such as for "Beast King Barbaros" and the ability to easily activate its field-clearing effect; Synchro Summons, if you revive Tuner monsters; or fodder for anything that needs large amounts of monsters on the field.

Psychic Assault
This deck is quite possibly the easiest of the Assault Mode decks to use due to the usability of "Overdrive Teleporter" and "Hyper Psychic Blaster" being a level 9 Synchro Monster. Thus, Special Summoning "Hyper Psychic Blaster" is as simple as Tribute Summoning "Overdrive Teleporter", Special Summoning at least one "Psychic Commander" and tuning "Teleporter" and "Commander" to Synchro Summon "Blaster". From there, activate "Assault Mode Activate" as soon as possible.

A notable feature of "Hyper Psychic Blaster" is the summoning condition. Unlike other Level 9 Synchro Monsters, such as "Mist Wurm" and "Trishula, Dragon of the Ice Barrier", "Hyper Psychic Blaster" only needs 1 other monster (at minimum) to Synchro Summon it. Most of these decks take advantage of this valuable fact as much as possible.

Rarely known as Plantic, Plants have a great swarm relation to Psychics. Plantic decks that involve "Hyper Psychic Blaster/Assault Mode" are surprisingly powerful. Using level 3 Plants (like "Lonefire Blossom"), level 3 Psychics (like "Psychic Commander"), level 6 Plants (like "Gigaplant") and level 6 Psychics (like "Overdrive Teleporter"), summoning "Hyper Psychic Blaster" is as simple as putting 3 and 3 and 3 together. If the deck is Plant-Heavy you can use "DNA Surgery" to change all types to Psychic for ease of summoning.

Flamvell Assault
This deck is based on tuning level 8 Synchro Monsters using "Flamvell Magician" and "Flamvell Firedog". "Firedog" Special Summons "Magician" quickly with his Effect and they could tune to make a level 8 Synchro Monster in Main Phase 2 after "Firedog's" Effect and the only thing you have to do is activate "Assault Mode Activate" as soon as you can. Also, you can activate "Rekindling" to return Flamvells and tune them again. "Return from the Different Dimension" helps you to return Flamvells after they were Removed from Play with "Rekindling".

Strategy of this deck is simple and you just have to summon "Firedog" as quick as you can and blow away your opponent with Synchro Monsters and /Assault Mode Monsters.

Assault Mode (AM) Monsters

 * Red Dragon Archfiend/Assault Mode - Basic sweeper if used correctly, good against swarm strategies.
 * Stardust Dragon/Assault Mode - Like the original, it can negate effects that may harm it and serve as a general wall.
 * Hyper Psychic Blaster/Assault Mode - One of the average Assault Mode monsters, it can do some damage when used correctly. The effect of this card is also good for a Burn Deck.
 * Arcanite Magician/Assault Mode - Play your Spell Cards quickly and keep this monster on defense to have a tank that can remove monsters with Spell Counters.
 * Doomkaiser Dragon/Assault Mode - This card's original counterpart can be summoned along with other Zombie-Type monsters, making for a swarm.
 * Colossal Fighter/Assault Mode - Good in a Warrior-based deck, and attack wise, it packs a punch.

Synchro Monsters

 * Red Dragon Archfiend
 * Stardust Dragon
 * Hyper Psychic Blaster
 * Arcanite Magician
 * Doomkaiser Dragon
 * Colossal Fighter

Monsters

 * Assault Beast - The best way to search for "Assault Mode Activate" so you can activate it and summon your AM monster(s) as quickly as possible. Also can become a handy beatstick if needed.
 * Assault Mercenary - This can bring "Assault Mode Activate" back to your deck from the graveyard and destroy a Spell or Trap card. Can be used as a good 1800 beatstick as well.
 * Arcane Apprentice - Effect serves as back-up.
 * Hyper Synchron - Good level 4 tuner, and gives Dragon Synchro Monster and 800 ATK boost. Use with "Assault Mode Activate" before the end phase to avoid Dragon Synchro Monster from being Removed from Play, e.g. during the Battle Phase to get an attack with both a Synchro and Assault Mode counterpart.
 * Blackwing - Gale the Whirlwind - Same reason as "Psychic Commander" except that "Gale" is DARK and has a built-in "Shrink" effect. It also gives you access to "Blackwing Armor Master".
 * Destiny Hero - Malicious - It can easily be dumped to the Graveyard (Armageddon Knight, Dark Grepher etc.) in order to easily tune with Krebons or Plaguespreader Zombie for a quick Stardust. It can also be used with a Destiny Hero engine along with Elemental Hero Stratos, Destiny Hero - Diamond Dude, and Destiny Hero - Dasher.
 * Night Wing Sorceress - Search out Assault Mode Activate, set the card, summon this Spellcaster, activate it.
 * Krebons - Searchable by Emergency Teleport, because this is a Level 2 Tuner, it can be quite versatile for summoning Synchros for your AM monsters.
 * Plaguespreader Zombie - A recyclable Level 2 Tuner that is Splashable in almost any deck.
 * Quillbolt Hedgehog - As above.
 * Psychic Commander - Mainly used for summoning odd-Leveled Synchro monsters, this card is also searchable by E-Teleport.
 * Summoner Monk - By having an unwanted Spell card in your hand to discard for a Level 4 Tuner, this card makes Synchro Summoning Level 8 Synchro monsters very easy.
 * Mist Valley Soldier - the now currently best Level 4 Tuner in TCG as well as very easy to summon out with Summoner Monk. "Broken Jack Atlus" uses a deck in Tag Force 4 that utilizes this exact strategy with great effectiveness.
 * Rose, Warrior of Revenge - What was the most widely used Level 4 Tuner in TCG simply due to availability, but with the release of Hidden Arsenal it shares the spotlight with Mist Valley Soldier.
 * A Cat of Ill Omen - Helps bring Assault Mode Activate to your hand with its effect.
 * Flamvell Magician - A good alternative to Rose, Warrior of Revenge or Mist Valley Soldier since it gets spellcaster-type support and more important, it avoids Bottomless Trap Hole. It also gets Flamvell support such as Flamvell Firedog and Rekindling.

Spells

 * Emergency Teleport - This card can quickly summon a Level 1, 2, or 3 Tuner from your hand or Deck, making it easy to Synchro Summon the monster you need.
 * Assault Teleport - With the cost of sending a /Assault's monster from your hand to your Deck, and then shuffle, you can draw 2 cards, a great card.
 * Mind Control - You can use this card to Synchro Summon easily and take away an opponent's monster.
 * Assault Overload - this card can finish off your opponent's lifepoints.
 * Pot of Avarice - Instead of worrying about keeping the /Assault Mode Monsters in your deck, send them to the graveyard, and when you're ready to activate them, use this card and draw two.
 * Magical Mallet - Use this if you ever do draw any /Assault Mode monsters, activate it so you can put them back in your deck, shuffle, and draw the same amount of cards you put in. It's better than Reload because you're bound to want to keep some of the cards in your hand, even if it's not quick play.
 * Card Trader - Great for putting your /Assault Mode monster back into the deck and getting another useful card. And unlike cards like Assault Teleport, this is useful even when you don't have an /Assault monster in your hand.
 * Lighten the Load - /Assault Mode monsters are usually higher than level 7, so you can put them back into the deck and get a new card.
 * Instant Fusion - Have a 4-star Fusion Monster ready with a 4-star Tuner in hand. Normal Summon the tuner, and special summon the fusion monster. Easy Synchro Summon!

Traps

 * Threatening Roar - This card can protect any Assault Mode monsters or just monsters that you don't want to have destroyed.
 * Good Goblin Housekeeping - Great card, you draw 1 card for each Good Goblin Housekeeping on your Graveyard +1(so, if you don't make chains of Good Goblin Housekeeping's copies you will draw 1 card the first time, 2 the second and 3 the last.) and then send 1 card to the bottom of your Deck(or have all three and play emergency provisions for a huge draw engine of 4 cards drawn per housekeeping you had)
 * Dark Bribe - Assault Mode Activate needs to tribute the synchro needed, this is a cost, if the Assault Mode Activate is negated, your synchro will never return because was a cost and more, and you will get nothing, use this card to counter cards like Solemn Judgment or the same Dark Bribe from your opponent.
 * Dimensional Prison - protects and monster you don't want to die, or if your assault mode has been tributed for its effect,(i.e. stardust) you can protect your life points with this.
 * Descending Lost Star - This card can special summon your synchro monsters from the graveyard making /Assault Mode monsters easier to summon
 * Wicked Rebirth - As above but better: if you don't have Assault Mode Activate for your revived synchro monster, you can still attack with it.
 * Assault Slash - This card lets you destroy all monsters on the field; a good strategy to win the duel!
 * Assault Counter - If you have this card, you can counter a Spell Cards, Trap Cards, or Effect Monsters like Dark Bribe Trap Stun and Man-Eater Bug

Strengths
Depending on how you build it, this deck can be very fast and very quick to kill your opponent. Decks that work slow or take a while to get started, like a Spellcaster Deck or Frog Deck, are at risk of destruction.

Stardust Dragon/Assault Mode makes short work of most monarch decks and Blackwing Decks and Red Dragon Archfiend/Assault Mode destroys Zombie Decks.

A great combo to have Stardust Dragon/Assault Mode and Red Dragon Archfiend on the field, attack with each one, play Assault Mode Activate on Red Dragon Archfiend, attack with him. If that is not victory, his effect will destroy Stardust Dragon/Assault Mode and you can either a) tribute Stardust Dragon/Assault Mode to bring back Red Dragon Archfiend to attack again b) attack with Stardust Dragon who was brought back by the destruction of Stardust Dragon/Assault Mode c) another kind of summoning the assault mode monster easily is combining Cursed Prison that will able you to summon any synchron but negate its effects and won't allow you to attack, with the properly Assault Beast, or Assault Mode Activate given you an instant /assault mode summoning

Weaknesses
Adding /Assault Mode support to your deck adds a new level of difficulty. Anti-Meta Decks will annihilate this deck. Always make sure to have a good side deck to deal with these decks. Also, because these decks are completely dependent on the use of Assault Mode Activate, the deck can be shut down by a simple Prohibition, so make sure to have spell and trap removal cards such as Twister or Mystical Space Typhoon.

Cards that can negate Assault Mode Activate like Dark Bribe and Trap Stun are very effective because they have to Tribute their Synchro Monster as a cost. Then they cannot summon the /Assault monster because Assault Mode Activate was negated.

Another /Assault Mode deck weakness is that if you draw an /Assault Mode monster, it is quite hard to summon. A way to solve this problem is to use Hand Destruction or Card Destruction, then use Pot of Avarice to return them to the deck, so make sure you have some of those cards in your deck. Also, your opponent must discard cards as well, so there is an added bonus to running these cards.