/Assault Mode

"/Assault Mode", known as "/Buster" (バスター Surasshu Basutā, read as "Slash Buster") in the Japanese version, is an archetype of monsters that are powered-up Effect Monster versions of already-existing Synchro Monsters, Special Summoned by using "Assault Mode Activate" on the corresponding Synchro Monsters. Aesthetically, the "/Assault Mode" cards are re-armored counterparts of the original monster.

This archetype was localized to "/Assault Mode" in order to convey a greater sense of power, according to Dan Scheidegger (an Upper Deck Entertainment employee) in a post on Pojo.

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 on the field). 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.

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" has a severe drawback).

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 destroy cards 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.

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 banished, 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 sent to the Graveyard ("Armageddon Knight", 'Dark Grepher" etc.) in order to 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 - Allows you to activate "Assault Mode Activate" the turn that you set it.
 * Krebons - Can be searched by "Emergency Teleport" and because it is a Level 2 Tuner it can be quite versatile for summoning Synchro Monsters for your AM monsters.
 * Plaguespreader Zombie - A recyclable Level 2 Tuner that is Splashable in almost any deck. It can also be useful way to return any "/Assault Mode" monsters you drew into the deck, ready to summon with "Assault Mode Activate".
 * Psychic Commander - Mainly used for summoning odd-Leveled Synchro Monsters, this card can also be Special Summoned by "Emergency 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 - Now currently best Level 4 Tuner in TCG as well as very easy to Special Summon 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 - 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".
 * Flamvell Magician - A good alternative to "Rose, Warrior of Revenge" or "Mist Valley Soldier" since it gets Spellcaster-type support and more importantly 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 Psychic 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, giving you a 2 for 2 (which is extremely useful since /Assault Mode monsters are useless in your hand).
 * Mind Control - You can use this card to Synchro Summon and take control of an opponent's monster.
 * Assault Overload - This card can finish off your opponent's life points.
 * Assault Revival - Useful for an extra attacker, once you attacked with all available monsters. To allow it to use its effects and not have it banished, use Book of Moon.
 * 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!
 * Fire Formation - Tenki - In some decks that lack cards to provide draw engine for Assault Mode Activate or Assault Beast, having some copies of Fire Formation - Tenki allow you to search Assault Beast, then you can discard Assault Beast for Assault Mode Activate.

Traps

 * Good Goblin Housekeeping - This is a great card in this type of deck since 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 return 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)
 * 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 such as "Solemn Warning", "Trap Stun", and "Snowman Eater".
 * Star Siphon - You can get a token which can be used for a Synchro Summon or a Tribute Summon as well as defense and while your Synchro Monster is reduced to level one, this doesn't matter as you will just Tribute it for "Assault Mode Activate".

Strengths
Depending on how you build it, this deck can be very fast and very quick to kill your opponent. Decks that work slowly 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 way to deal massive damage to your opponent's life points is to have your Synchro Monster of choice on the field. "Hyper Psychic Blaster" will deal the most damage but "Stardust Dragon" has the greatest chance of working. Attack with the Synchro Monster, then use "Assault Mode Activate". You can also chain "Assault Mode Activate" to a "Mirror Force" or "Dimensional Prison" to avoid the loss of your monster and maintain field advantage. Then, attack with the /Assault Mode Monster. Activate "Assault Overload" and inflict damage to both players equal to the /Assault Mode Monsters' level X 200. Then attack with your original Synchro Monster and if your opponent has a clear field or you used "Hyper Psychic Blaster/Assault Mode" then you will win.

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 "Prohibition" so make sure to have Spell and Trap removal cards such as "Dust Tornado" or "Mystical Space Typhoon".

Cards that can negate "Assault Mode Activate" like "Dark Bribe" and "Trap Stun" are very effective against this deck type because you still lose your Synchro Monster.

Another /Assault Mode deck weakness is that if you draw an /Assault Mode monster it will waste your draw. 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.

If an /Assault Mode Monster (except Stardust Dragon/Assault Mode where it can negate effects) is destroyed by "Ryko, Lightsworn Hunter", its original form cannot be revived because Ryko's self-milling is the last thing to happen, not the destruction, due to Missing the timing.

Doomkaiser Assault
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.

Arcanite 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 the ATK of "Arcanite" 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.

Stardust / Red Dragon / Colossal 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 4 or 5 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 banishes 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". "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.

Flamvell Assault
While relying on Malicious to Synchro Summon "Stardust Dragon" can be unreliable, using Flamvells to summon a Stardust can be surprisingly easy. Destroy one of your opponent's monsters with "Flamvell Firedog" (Level 4) and Special Summon "Flamvell Magician" (Level 4 tuner). Tune them together for a "Stardust Dragon". Also, once a sufficient amount of Flamvells have been added to your Graveyard, "Rekindling" is a quick and easy way to Synchro again for "Stardust Dragon".

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.

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.

Dragunity Assault
Use the field spell "Dragon Ravine" to send "Dragunity Phalanx" to Graveyard and search out "Dragunity Dux"; Normal Summon it and use it's effect to equip "Dragunity Phalanx"; Special Summon "Dragunity Phalanx" and Synchro Summon "Dragunity Knight - Vajrayana" because it can equip "Phalanx" again, letting you summon "Stardust Dragon".

This deck is based on tuning Level 4 non-Tuner Winged Beast-Type monsters with Level 2 Dragon-Type Tuner to summon "Dragunity Knight - Vajrayana". Special Summoning "Dragunity Arma Mystletainn" from hand can lead to summoning "Stardust Dragon". Strategy of this deck is simple and you just have to use "Dragon Ravine" as early as possible to spam Synchro Monsters and /Assault Mode Monsters.

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.

Ultimaya Tzolk'in Assault Mode
This build is centered around "Hieratics" and throwing out "Ultimaya" using "Labradorite Dragon" and going for "Stardust Dragon/Assault Mode" with setting "Assault Mode Activate". The Deck is fairly straight forward and easy to learn, and you have access to all of the other "Hieratic" staples. You also should run "Quickdraw Synchron" and "Magical Mallet" so you can shuffle "Stardust Dragon/Assault Mode" back to the Deck. It also helps against dead hands, which happens often in "Hieratics".

For getting "Ultimaya" out, you can run cards like "Cyber Dragon" and "Wattaildragon". Any Level 5 vanilla Dragon is also a option, but is not recommended. You can also run "Instant Fusion", but lowers the speed of the Deck. The Deck has access to all Level 7 & 8 Dragon Synchros, such as "Beelze of the Diabolic Dragons" and "Black Rose Moonlight Dragon".