Crystal Beasts are an Archetype introduced in Yu-Gi-Oh! GX, originally piloted by Jesse Anderson. They are based on various Gems and are named after various animals. Each Crystal Beast shares the ability to reside in the Spell/Trap Zone, with Spell Card and Trap Card support cards whose effects use the "Crystalized" form of the beasts.
Despite being an abandoned Archetype which has received no support past their debut until recently, their Spell Card and Trap Card support give them a myriad of effects allowing further survivability, with Crystal Abundance allowing for an OTK to be achieved.
- Crystal Beast Amber Mammoth
- Crystal Beast Amethyst Cat
- Crystal Beast Cobalt Eagle
- Crystal Beast Emerald Tortoise
- Crystal Beast Ruby Carbuncle
- Crystal Beast Sapphire Pegasus
- Crystal Beast Topaz Tiger
 Game Play
Crystal Beasts, when destroyed while face-up, have the option to be put in the Spell/Trap Zone instead of going to the Graveyard. Their Spell and Trap support revolves around abusing the Crystal Beasts in the backrow, ranging from filling the backrow up with more Crystal Beasts to using Spells and Monster effects to swarm the field.
 Building the Deck
 The Core
These are the cards that should be included in every Crystal Beast deck regardless of what the meta looks like.
The set up and one of the two most important Crystal Beast monsters. Sapphire Pegasus, along with Ruby Carbuncle, take priority over every single other of the Crystal Beasts when it comes to deck space. When he's summoned in any way, he can bring along a friend from anywhere except the banished zone to be placed in the Spell/Trap zone. This helps set up the Spell support as well as helps keep Rainbow Ruins alive. In addition, he is the biggest Crystal Beast in terms of attack, not counting the boost Topaz Tiger gets, so will be one of your beatsticks.
The play maker and the other most important Crystal Beast. When Ruby Carbuncle is special summoned in any way, he brings along every one of his friends in the backrow. This helps set up Xyz plays or at the least grants several beatsticks to swing at the opponent with. At 3, Ruby Carbuncle tends to become a dead draw, while at 1, if you DO draw it, it hinders your plays quite a bit, so 2 leaves Ruby Carbuncle less likely to be drawn and, if he is, doesn't hinder you much.
The beatstick of the deck. After Sapphire Pegasus and Ruby Carbuncle are in the deck, any other Crystal Beast is added just to increase the Crystal Beast count to make Sapphire Pegasus, Ruby Carbuncle and the Spells more live.
As with Topaz Tiger, merely another beatstick and monster for the Crystal Beast count. Usually a personal preference over whether to use Amber Mammoth or Topaz Tiger, as they both fill largely the same role.
While generally used for the same reasons as Topaz Tiger and Amber Mammoth, Emerald Tortoise DOES have two difference that make it a viable option over those two. First, Emerald Tortoise has a beefy defense, which can catch an unprepared opponent by surprise and can help you wall for a while. In addition, Emerald Tortoise is level 3, meaning that, when combined with Ruby Carbuncle, can grant you access to powerful Rank 3s, an option that shouldn't be immediately overlooked.
The Crystal Beasts' Field Spell and arguably the most powerful Field Spell out. With an astounding five effects, depending on the amount of Crystal Beasts in your Spell/Trap zone, this card can easily alter the outcome of the game. With its first effect, Rainbow Ruins can be used in conjunction with Scrap Dragon for free destruction of your opponent's cards, as well as used as an out to your Zenmaines' effect activating in the End Phase and your opponent having no cards on field to destroy.
1-2x Crystal Beacon
The themed Summoner Monk. This card allows you to bring out ANY Crystal Beast monster from your deck, including Sapphire Pegasus for more backrow filling or Ruby Carbuncle for mass swarming. Be warned, however; Crystal Beast decks tend to only run about 9-12 Crystal Beasts in the deck, so Beacon is not recommended to be run at 3 to avoid it being dead.
2-3x Crystal Promise
When Rainbow Ruins is no where to be found or you can't find yourself able to fill up your backrow fast enough to set off Rainbow Ruins' 5+ effect, Crystal Promise is there to get things going. Doing as little as bringing out a Topaz Tiger for offense/defense to bringing out a Sapphire Pegasus to grabbing more Crystal Beasts from your deck to bringing out Ruby Carbuncle and all the other Crystal Beasts that will hanging out with Ruby Carbuncle in the backrow, Promise can help make plays happen and should definitely be run.
The jack of all trades for Crystal Beasts. It gives a healthy boost to any Crystal Beast monster, making Sapphire Pegasus and Topaz Tiger quite difficult to deal with for the opponent. Release also helps you fill your backrow once its time on the field has ended by grabbing a Crystal Beast from your deck. However, probably the most unique part about Release is that it activates whenever it's sent from the field to the graveyard, including when destroyed while face-down, meaning it's a perfect bluff to set and fool your enemies into MST'ing.
2-3x Rare Value
The "Draw 2" of the deck. This card can help speed through the deck at the cost of a Crystal Beast in your backrow. This can help with freeing up the backrow if it's starting to clog up before you can do anything to abuse them or if you're in desperate need of drawing. The one downside to this card is that your opponent gets to pick which gets sent to the graveyard instead of you.
 The Staples
While not a key part of the deck, they still are key in winning duels and should be added before any techs.
1x Dark Hole
Dark Hole is staple for a reason and one we can easily use. Clearing the field is always nice.
2-3x Pot of Duality
Duality gives Crystal Beasts much needed speed to getting to the key cards of the deck, making it that much faster for Sapphire Pegasus to reach your hand or Ruins to come out.. The "No Special Summoning this turn" part of the card can hurt Crystal Beasts if you plan on making a push for advantage or game, but the trade off is worth the speed it grants to Crystal Beasts.
 Cards That Change With the Format
These are the cards that fall in and out of usefulness depending on the format. They may shine in one format, but then prove to be inadequate in the next.
 Common Techs
These are the cards you add to the main deck after you have your core established. They provide support to help the deck succeed. Many Techs work equally well in the main deck or side deck.
Zephyros is amazing in this deck because he allows you to bounce your backrow to make room to activate other Spells. This includes bouncing a Sapphire Pegasus for reusing later and bouncing Rainbow Ruins to get another free draw off it. Combine with Summoner Monk for easy summoning and set up.
2-3x Effect Veiler
This nifty hand trap has slowly gotten more popular in the past few formats due to its ability to stop key plays when used correctly and having very few true counters. This card is especially useful in Crystal Beasts from the lack of traps to stop the opponent's monsters.
Fossil Dyna has one job and it does it well: Keeping the field clear of Special Summons. So long as he's face-up, neither player can attempt a Special Summon at all. Fossil Dyna's one downfall is its mediocre stats, which will have it run over very fast.
0-2x Genex Ally Birdman
Birdman is a three option bundle: He can bounce Sapphire Pegasus for reusing him later and giving you a 1900 attack monster on the field; opens up Synchro plays for this deck, giving us access to Brionac, Gaia Knight, Scrap Archfiend, Black Rose Dragon and, if ran with Summoner Monk, Arcanite Magician; and finally, Birdman gives you access to Rank 3s if you choose not to run Emerald Tortoise. Birdman is all around a solid card to run should you choose.
Malefic Stardust makes all your opponent's Mystical Space Typhoons, Graphas, Ryko, Lightsworn Hunters and other spell/trap hate less effective. However, Malefic Stardust is less useful in this deck as Rainbow Ruins already has built in protection. A good monster, but outclassed in this deck.
Similar to Malefic Stardust, but with 1500 more attack points and a Field Spell that is difficult to remove, making Malefic Cyber End the better choice in this deck. Nearly impossible for an opponent to get a bigger monster out, but still susceptible to effect removal.
0-1x Scrap Beast
Another option for accessing Synchros in the deck, Beast gives you the option of going for level 8 Synchros, namely Scrap Dragon and Stardust. Able to be special summoned by Summoner Monk and if you use him to attempt to Synchro a Scrap Dragon and your opponent uses Solemn Warning or Solemn Judgment on him, Scrap Dragon's effect will still activate, giving you back Beast.
0-2x Summoner Monk
An amazing card in this deck. Able to bring out Sapphire Pegasus for a +1, Zephyros for set up later on or another of the level 4 Crystal Beasts for an instant Xyz. If you do run Monk, you will need a large Spell card count to make sure he's live, usually 20+ Spells. An interesting combo to note with Monk is to Normal Monk, discard a Spell, Special Sapphire Pegasus and put another Crystal Beast in the backrow, then bounce Sapphire Pegasus for Birdman, Synchro for Arcanite Magician for 2 free pops and a nice wall.
0-2x Thunder King Rai-Oh
As this deck does very little searching and adding to hand from deck, along with very little Traps to stop opponent's plays, Rai-Oh can be an effective add to the deck to slow the opponent down and stop your opponent from doing a Synchro or Xyz summon, while providing a nice beatstick for the deck.
0-1x Crystal Tree
Tree can help set up for the other Crystal Beast Spell cards and speed the deck up immensely, but has one huge downside. To send Tree, you must special EXACTLY the amount of Crystal Beasts as the number of counters on Tree. If you have 4 counters on Tree but only 2 spaces open, you cannot send Tree. Tree can either help or hurt you immensely and is very much a preference if you choose to run it.
0-2x Forbidden Lance
As all the Crystal Beasts are generally small and you don't want to Synchro or Xyz very often to make sure the Crystal Beasts make it to the backrow, Lance is a good option for getting over your opponent's monsters, as well as saving your monsters from Bottomless Trap Hole and Dimensional Prison.
Due to the nature of Crystal Beasts taking up much room in the backrow, Spells and Traps that tend to sit in the backrow for a while waiting to be activated should be avoided. As this is the case, you generally have to deal with your opponent's backrow without cards like Dark Bribe and Solemn Judgment there to stop them. Maxing on Typhoon means you can get rid of as many of those as possible without having to run into them with your monsters.
0-3x Smashing Ground
As with Lance, Smashing Ground is an excellent way for this deck to deal with opponent's monsters that Crystal Beasts can't get over.
Due to the lack of traps in the deck, Crystal Beasts don't have a real way of dealing with an opponent who's already gained an offensive edge. Swords helps by stalling for 3 turns so you can gather more resources to make a counter attack, as well as not clogging the backrow for too long.
Useful for grabbing Rainbow Ruins faster and thinning the deck out so you don't draw into the Ruins too late in the game.
A highly useful card in Crystal Beasts. Gives a large bonus to Sapphire Pegasus, Amber Mammoth, Topaz Tiger and Amethyst Cat, as well as netting draws for great plussing.
An extremely useful card in Crystal Beasts. Can be used to either get rid of 2 opponent's monsters and catch them off guard or be used to destroy an opponent's monster and a Crystal Beast, which will just go to the backrow, giving you the fuel you need for the deck's Spells.
Note: It's highly ill advised to run other Traps with Treacherous, as if any of them get destroyed or used before you use Treacherous, it becomes useless in this deck, as discards don't happen aside from Monk and Brio, with Monk only discarding Spells.
 Extra Deck
Run only if you run Cyber Dragon in your side.
Run only if you run Malefic Cyber Dragon.
0-3x Stardust Dragon
Run only if you run Malefic Stardust.
0-1x Wind-Up Zenmaines
0-2x Gem-Knight Pearl
The biggest Rank 4 out currently. No effect, but makes up for it by being able to run over most Xyzs out currently.
The Rank 4 Zenmaines. Can save himself up up to twice, or can set an opponent's monster to be able to run over easier. Very solid monster and easily worth the Extra Deck space.
Can help push for game or hinder your opponent immensely, as well as having decent attack.
2-3x Number 39: Utopia
Sizeable Xyz and decent stalling effect. When the materials are up, you can easily drop Utopia Ray to avoid Utopia destroying himself.
Use to save your Utopias from self-destructing, or from dropping on an opponent's Utopia that you stole with Puppet Plant.
Useful for destroying an opponent's Spirit Reaper or getting over a stronger opponent's monster.
Slowly lost usefulness with the fall of Synchros, Roach has however gained a bit more use with the rise of Chaos Dragons, capable of severly hindering anything they can do, leaving them only able to get rid of Roach with Ryko or Dark Hole.
 Skeleton Decklist
 Why Aren't These Cards Used?
These cards aren't run for a variety of reason, ranging from being too difficult to successfully play, to just plain outclassed by other cards. Traps in general are not run in Crystal Beasts due to clogging the backrow unless they are greatly helpful for keeping resources coming(Horn of the Phantom Beast) or are easily activated at any time(Treacherous Trap Hole). Most Staple Traps do not fall into either of these categories, so they will not be covered in this section. The themed Traps will be the only Traps covered in this section.
The "self-Raiza" of the deck. Cobalt is not used for several reasons. He clogs up your next draw, slowing you down from reaching key cards. The only Crystal Beast you'd ever want to spin to the top of the deck to reuse the effect of is Sapphire Pegasus, but Genex Ally Birdman outclasses Cobalt Eagle, since he returns to the hand, resulting in your next draw being unclogged. Run this if you're playing a Rainbow Dragon deck, but otherwise, Birdman is the true feathered friend of Crystal Beasts.
Back when Rescue Cat was not Forbidden, Rescue helped set up Crystal Beasts amazingly due to giving two Amethyst Cat to the backrow to fuel the Spells of the deck. Without Rescue, Amethyst Cat is far too weak to be used for beating and is outclassed by Emerald Tortoise in terms of Level 3s for Rank 3s. As of current, with Rescue Forbidden, Amethyst only has some viability if used with Horn of the Phantom Beast, but is still outclassed by Sapphire Pegasus, Topaz Tiger and Amber Mammoth for Horn abuse. As with Cobalt Eagle, run this card in a deck focused on Rainbow Dragon; otherwise, Amethyst Cat should just wait and hope for Rescue Cat to return.
The boss monster of the archtype. There's two reasons why Rainbow Dragon isn't run and their names are Cobalt Eagle and Amethyst Cat. To use Rainbow Dragon, you're forced to play at least one of ALL the Crystal Beast monsters; without them, Rainbow Dragon is unsummonable. With them, however, the deck becomes much more inconsistent. Rainbow Dragon's effects are also mediocre and do nothing to support the deck's focus around Crystal Beasts in the backrow. Run in a deck dedicated to bringing Rainbow Dragon out, but in competitive Crystal Beasts, Malefic Cyber End Dragon outclasses him.
The alternate Field Spell for the deck and a recent addition to the Crystal Beast arsenal. So why is this card passed up so soon after being released? The answer is simple: Ancient City - Rainbow Ruins. Rainbow Ruins is one of the best Field Spells in the game that would require a truly amazing Field Spell to replace it. Advanced Dark doesn't quite make the "amazing" category. While not as good as Rainbow Ruins, it DOES have some unique bonuses to it. Advanced Dark helps set up Rainbow Dragon easier by helping you send Crystal Beasts from the deck to the graveyard, making you less likely to draw the Crystal Beasts you DON'T want to draw, namely Ruby Carbuncle, Amethyst Cat and Cobalt Eagle. Advanced Dark also grants you access to the DARK boss monsters, such as Dark Armed Dragon and The Dark Creator. While not viable in a "competitive" Crystal Beast deck, this card shines in a Rainbow Dragon or Evil Jesse Anderson deck.
A card for searching Rainbow Ruins, but a rather disappointing one. Being a trap, having a restrictive activation time and the existence of Terraforming means this card just isn't worth the deck space in Crystal Beasts.
A rather interesting card. Can help you set up the 5+ effect of Rainbow Ruins, which, if you have Ruby Carbuncle as one of your backrow selections, can help you set up a few Xyz and/or Synchro summons, or just allows you to fill your backrow up with Crystals if you were run thin. Counter can also help you set up Crystal AbundanceThe card does have a few flaws, however. The card can be dead if you draw it early and have little to no Crystal Beasts. It can also clog the backrow if you set it before you're ready to activate it, which can prevent you from activating some crucial Spells. Finally, it forces you to send Rainbow Ruins, as Rainbow Ruins can not protect itself from being SENT to the graveyard. A very much "big risk, big reward" card that can be run if you feel lucky. Otherwise, Treacherous is the safer route.
Outclassed by Mystical Space Typhoon for Spell/Trap removal and outclassed by Treacherous for Monster removal, this card also has the downfall of sending a Crystal Beast from the backrow to the grave for little return. Not recommended over the aforementioned MST and Treacherous.
Good for running in a deck dedicated to Rainbow Dragon, but not worth it in competitive Crystal Beasts.
As with Rainbow Path, a good in (and only viable in) a deck dedicated to Rainbow Dragon, but not in the competitive build.
Decent for thinning the deck out and saving yourself from damage for a turn, but the restrictiveness of the activation of this card is very off-putting. Viable in a Rainbow Dragon deck, but not recommended for competitive.
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