"Crystal Beast", known as "Gem Beast" (宝玉獣Hōgyokujū) in Japan, is an archetype of Monster Cards that all share the effect of becoming Continuous Spell Cards upon their destruction. Although weak in terms of actual strength, their aforementioned effects allow them to have great staying power. In addition, they are supplemented by many support cards which utilizes them in their Continuous Spell Card form. When all seven Crystals are on the field or in the Graveyard, their boss monster, Rainbow Dragon, can be Summoned. This archetype also contains one of the most powerful OTK setups with "Crystal Abundance", and even sturdy control with the five effects of their field spell.
The "Crystal Beasts" made their first appearance in the Yu-Gi-Oh! GX anime, used by Jesse Anderson. In the English dub, each one of the "Crystal Beasts" monsters, except "Ruby Carbuncle", imitates the voice of a real life movie celebrity. Upgraded forms, the "Advanced Crystal Beasts", would later be used.
The "Crystal Beasts", whose original name is "Gem Beasts", as their name says, are all animals which have each a different kind of gem in their bodies. Their different gems' colors form the seven colors of the rainbow, reflecting the name and design of their ace, "Rainbow Dragon". Their nomenclature is "Crystal Beast (gem) (animal)", and their attack names are "(gem) (part of their body/attack)".
"Crystal Beast" Decks tend to have a wide variety of searching options for putting "Crystal Beast" cards on the field, either Summoned as monsters or placed in the Spell & Trap Card Zone as an effectless Continuous Spell Card, and they have a couple of extra drawing options to speed up the use of the Deck. Because of these effects working together, "Crystal Beast" users can wind up many cards ahead of their opponent, and the various searching options facilitate the Summoning of "Rainbow Dragon" far quicker than would otherwise be possible. The archetype also supports come-from-behind wins quite easily due to the double whammy of "Crystal Abundance", which wipes out everything on the field and then swarms the field with monsters from the Graveyard, and the Field Spell Card of the set, "Ancient City - Rainbow Ruins", gains a new effect for every Continuous Spell Card "Crystal Beasts" you control. The archetype is also somewhat resistant to opponents who use Spell and Trap destruction effects, as a couple of cards can quickly put the "Crystal Beasts" in Spell form back onto the back row from the Graveyard, and the Field Spell Card resists being destroyed itself.
It should be noted that, although "Rainbow Dragon" is the boss monster of this archetype, its inclusion is more likely to be a great monster, you need a good strategy to get Crystal Beasts out in one turn; maybe two turns if your hand is not good. Because of this, "Hamon, Lord of Striking Thunder" is often used in its place, but "Malefic Cyber End Dragon" avoids both the lengthy set-up and the hefty costs of the previous bosses, and boasting the same 4000 ATK but it can be removed easily from the field due to the fact that it gets destroyed once your Field Spell card is removed from the field. Malefic Cyber End Dragon requires a Field Spell to be Summoned and is the only monster to attack once it is on the field, so you may not want to put this card in your Deck.
With the introduction of Xyz Monsters, "Crystal Beasts" have become a more difficult Deck to use. With impressive swarming abilities, a "Crystal Beast" player can easily Xyz Summon two or three times in one turn. However, when these Xyz Monsters are destroyed, all of those "Crystal Beasts" will be trapped in the Graveyard, requiring slow pick-up from "Sapphire" Summons, or risking "Crystal Blessing", which will not always have targets. The key is to Xyz Summon only when absolutely necessary, as excessive overlaying will exhaust the Deck's longevity in no time.
If a card such as "Macro Cosmos" is preventing cards from reaching the Graveyard, this will NOT prevent "Crystal Beasts" from using their effects (as they would never hit the Graveyard in the first place).
The OTK is more competitive friendly. It utilizes the effect of "Crystal Abundance" to work, so a few copies of the card is essential to have in the Deck, as well as a way to search it out ("Different Dimension Capsule" or "Gold Sarcophagus" work nicely). There must be four Crystal Beasts in the Spell & Trap Zone, plus an open slot to activate "Crystal Abundance". Wait until you have five Crystal Beasts on the field or in your Graveyard with ATK of 1600 or more to activate the card. Upon activating "Crystal Abundance", if your opponent had at least five cards on his/her field, all five of your monsters can be Special Summoned. "Crystal Abundance" leaves your opponent open to a direct attack. Another way to achieve this outcome is by the use of the Destiny Heroes. With the combination of the various normal spells and "Destiny Hero - Diamond Dude", it can make a speedy Deck. A great way to speed up the process for "Crystal Abundance" is to play "Crystal Tree" because you just need to play it and ensure that two "Crystal Beast" are destroyed and become "Crystals" and then use "Crystal Tree" to finish the other required half for "Crystal Abundance. Just be careful with Tree as it has an annoying side effect: if it has more counters than you have spaces, you can't send it to the graveyard. As soon as it gets to 5 counters, you can't get rid of it. Keep "Mystical Space Typhoon" handy just in case.
You can also use "Flamvell Firedog" to easily search for "Flamvell Magician". You can also use "Dragon Queen of Tragic Endings" with "Krebons" to Synchro for a Level 8 Synchro Monster, and if you have any Crystal Beast in your Spell & Trap Card Zone, you can bring back "Dragon Queen of Tragic Endings" on the next turn. You can mainly abuse the powers of rescue cat in Synchro Summoning for this Deck. Mainly use Level 2 and 3 Tuner monsters and Level 5-7 Synchro monsters.
Synchro-Crystal Beasts featuring Brionac, Dragon of the Ice BarrierEdit
If you have an active "Ancient City - Rainbow Ruins" with 4 or more Crystal Beast Spells you can draw 1 card per turn, however, that 'once per turn' will no longer apply if "Ancient City - Rainbow Ruins" is removed from the field. Discard 1 card to activate the effect of "Brionac, Dragon of the Ice Barrier" then activate "Ancient City - Rainbow Ruins" and activate its fourth ability to draw another card. Repeat this as many times as you like. This loop is useful with "Exodia the Forbidden One" (See Exodia OTK for more details. For maximum results just send all powerful monsters to the Graveyard, save a "Crystal Abundance" (assuming you have four Crystal Beasts as Continuous Spells). Also until you have a "Mage Power". Use "Crystal Abundance" then Special Summon your Beasts (works well if opponent has a minimum of 4 cards), mainly "Crystal Beast Sapphire Pegasus" for an automatic three Crystal Beast Spells and a 2000 ATK boost to a monster. Attack and enjoy your victory.
This Deck is based upon getting "Rainbow Dragon" with ease with the help of Lightsworn monsters, "Charge of the Light Brigade" and "Solar Recharge"s. The milling helps to accumulate the seven Crystal Beasts in the Graveyard, making for the easy Summoning of "Rainbow Dragon". It will require 3 "Rainbow Gravity"s and 3 "Monster Reincarnation"s. The choice of your Lightsworn monsters are completely up to you. Adding the stronger Lightsworns like 'Jain, Lightsworn Paladin' to give this Deck more 'fire-power' also helps as you are able to keep attacking your opponent whilst being able to mill those 7 crucial Crystal Beasts in order to Summon Rainbow Dragon.
This Deck may be ineffective as when the "Crystal Beasts" are detached, they are sent to the Graveyard instead of going to the Spell & Trap Card Zone, as their effects don't activate while overlaid. Adding "Crystal Blessing" may help resolve this problem.
The management of maintaining vacant Zones in the Spell/Trap Card Zones can be irksome sometimes for these kind of Decks due to the balance between "Crystal Beast"s in said Zone for certain support cards as well as regular Spell/Traps to help this Deck further, a possible annoyance that can be hustled via cards like "Xing Zhen Hu", "Xing Zhen Hu Replica" and "Seismic Shockwave".
Beatsticks and Beatdown Decks if used early on and powered up a bit, can possibly deter "Crystal Beast"s as a majority of them have inadequate ATK and DEF.