Krawler " Krawler " is an archetype of Level / Link 2 EARTH Insect monsters introduced in " Circuit Break " . The archetype is related to , and is supported by , the " World Legacy " archetype . Design . According to the lore of " Beckoned by the World Chalice " , the " Krawlers " are the enemies of the " World Chalice " . Their names and designs are based on the human nervous system . Playing style . The " Krawler " archetype ' s main goal focuses upon using sheer numbers to overwhelm the opponent by swarming the field with as many of its monsters as possible . As the archetype is primarily comprised of Flip monster s , there is a focus in first getting them flipped face - up in order to trigger their Flip effect s , putting them in a position to then accomplish said main goal . The archetype does this through effects possessed on all of its monsters whereby two " Krawler " monsters are Special Summoned when the monster is removed from the field due to an opponent ' s card effect , effectively doubling the controller ' s field presence as a result . As the monsters need to be face - up for the effect to activate and said effect Special Summons more " Krawler " monsters face - down , this provides an incentive for the controller to first flip them face - up in order to utilize the Flip effects , then have the opponent remove them with a card effect in order to make full use of both effects . In order to ensure that this shared effect can trigger , the archetype also has a secondary aim of restricting the opponent ' s moves by complicating their attempts to remove its monsters from the field through destruction by battle . The archetype ' s Main Deck monsters are completely comprised of Flip monster s , each with two effects . The first effect is a Flip effect that is unique to the monster , and focus upon either advancing the player ' s resources or destroying cards on the field . The second effect is a common Trigger Effect that activates if they leave the field due to an opponent ' s card effect while face - up and controlled by their owner , enabling the controller to Special Summon 2 " Krawler " monsters with different names from their Deck in face - down Defense Position , with the exception of a monster that has the same name as the monster that left the field . The archetype ' s Link Monsters , all being Link 2 and able to be Link Summoned using 2 members of the archetype , all share a common effect wherein if they leave the field by being destroyed by battle or due to an opponent ' s card effect while face - up , the controller can Special Summon 2 " Krawler " monsters from their GY in face - down Defense Position , once again increasing their field presence and enabling the controller to perform another Link Summon later on . This effect also forces the opponent into a position whereby any form of removal will trigger it , thus playing into the archetype ' s strategy of manipulating the opponent ' s removal options . The archetype ' s Link Monsters also possess unique effects that augment the battling capabilities of its monsters , making up for their low ATK and enabling the archetype to be a capable threat in battle . " X - Krawler Neurogos " and " X - Krawler Synaphysis " share many common traits , namely that both possess Left and Right Link Arrow s , and grant " Krawler " monsters linked to them 300 ATK and DEF , and indestructibility by battle . The latter trait is particularly useful for the archetype , as it further cuts off the opponent ' s options in removing the archetype ' s monsters by battle and forces them to use card effects , thus triggering the common effect of the Flip monsters . Additionally , " Neurogos " doubles the battle damage that " Krawler " monsters linked to it inflict upon the opponent , while " Synaphysis " enables " Krawler " monsters linked to it to make 2 attacks on the opponent ' s monsters during the Battle Phase , traits that further bolster the archetype ' s capability to inflict mass damage to the opponent in concert with its ability to swarm . Due to the positioning of the Link Arrows for " Neurogos " and " Synaphysis " , the controller can only take advantage of their linked effects while they are in Main Monster Zones . However , the controller can use this trait to their benefit , as for greater protection , copies of " Neurogos " and " Synaphysis " can be co - linked to each other , enabling them to mutually increase each others ' ATK and protect each other from battle destruction , traits that they can bestow upon other " Krawler " Monsters , but not themselves . While it possesses stronger unique effects than " Neurogos " or " Synaphysis " , " X - Krawler Qualiark " is heavily dependent on the archetype ' s ability to swarm , as it applies its effects based on the number of " Krawler " monsters that the controller controls . However , like the unique effects of " Neurogos " and " Synaphysis " , such effects provide potent boosts to the archetype ' s battling capacities . Should the controller control 2 or more " Krawler " monsters , the ATK and DEF of all monsters the player controls are bolstered by 300 , similarly to the common effect of " Neurogos " and " Synaphysis " . The controller controlling 4 or more " Krawler " monsters prohibits the opponent from activating cards and effects during the Battle Phase . Finally , if the controller controls 6 or more " Krawler " monsters , monsters they control can attack the opponent directly . Because " Qualiark " possesses Bottom - Left and Bottom - Right Link Arrows , it serves the archetype best if it occupies the controller ' s Extra Monster Zone , as in that role , it can act as an initiator for other Link Summons and facilitate the ideal placement of copies of " Neurogos " and " Synaphysis " in the Main Monster Zones , and by extension , the construction of a series of such monsters co - linked with each other in order to reap mutual benefits . Given that the archetype is related to the " World Legacy " archetype , it also enjoys some support from that archetype ' s cards . The archetype ' s associated " World Legacy " monster , " World Legacy - " World Armor " " can be Special Summoned from the controller ' s hand when a monster is Flip Summoned , which can be easily enabled within the archetype . However , should it be Normal or Special Summoned , " World Armor " possesses an effect wherein the controller can search out a " World Legacy " card from their Deck to add to their hand , providing the controller with a way to search out support for either its archetype or the " World Legacy " cards connected to the " Krawler " archetype . Additionally , if it was Normal Summoned or Set , " World Armor " also has a Quick Effect that allows the controller to return both itself and a face - up monster controlled by the opponent that was Special Summoned from the Extra Deck to the hand , allowing for the removal of such monsters that may threaten the controller ' s efforts to build a field with " Krawler " monsters . Despite " World Armor " being a Level 7 monster , it can easily be Normal Summoned or Set in a " Krawler " deck , as the archetype provides ample Tributes for it due to its common effects . Due to its high ATK and DEF , " World Armor " also allows the archetype a way to cover for the fact that its own monsters tend to be lacking in those stats . The archetype ' s associated " World Legacy " Field Spell , " World Legacy in Shadow " has an shared effect with other " World Legacy " Field Spells in that it bolsters the ATK and DEF of the associated archetype ' s monsters by 300 . Additionally , " Shadow " has two unique effects , the first being that it allows the controller to Special Summon a Level 2 or lower Insect monster from their hand in face - up or face - down Defense Position , giving the archetype a more reliable way to amass field presence either to initiate their swarming capabilities or gather monsters to use as Link Materials for a Link Summon . The second unique effect of " Shadow " triggers in response when the controller ' s Flip monster is destroyed by battle by an opponent ' s monster , allowing the controller to send that opponent ' s monster to the GY , which serves as a way to further dissuade the opponent from attacking " Krawler " Flip monsters and preventing their common effects from triggering . Because the opponent might be more weary of attacking Set monsters as a result of this effect , it also allows the controller a greater opportunity to Flip Summon the archetype ' s monsters themselves , providing a more reliable way to Special Summon " World Armor " via its Summoning condition . In a pinch , " World Legacy Pawns " allows the controller a quick way to trigger the Flip effects of the archetype ' s Flip monsters , as it possesses an effect that can change a face - down monster the controller controls to face - up Attack or Defense Position . This is particularly useful if the opponent attempts to remove the controller ' s face - down " Krawler " monsters with card effects , as this effect will ensure that such monsters are face - up instead when they leave the field and can thus activate their common effects . " Pawns " also has another effect whereby the controller can return a " Krawler " monster from their GY to their Deck to flip a face - up monster they control face - down . Such an effect alleviates the fact that the archetype can potentially thin the Deck very quickly , especially if the controller is successful in consistently utilizing the common effects of the Flip monsters , while also enabling the controller to re - use the Flip effect of a " Krawler " monster . Due to the archetype largely consisting of Flip monsters , " Book of Eclipse " , " Book of Moon " , and " Book of Taiyou " can be used to great effect to trigger their Flip effects or Set them face - down again . As the archetype is reliant on Link Summoning its Link Monsters as quickly as possible in order to enable that its Flip monsters are reliably protected from battle destruction , cards such as " Multiplication of Ants " , " Worm Bait " , and " Spider Egg " can help in Special Summoning Token monsters to use as Link Materials , making up for the fact that the archetype can be slower to initiate its swarming capacity compared to other archetypes . If the controller is unable to dissuade the opponent from destroying " Krawler " Flip monsters by battle , " Verdant Sanctuary " can be a viable option in order to prevent the controller from losing card advantage should their monsters be destroyed , though it can also be used in concert with the common effects of the " Krawler " Flip and Link Monsters as well . Due to the tendency of the archetype ' s Flip monsters to be sent to the GY either because they were flipped face - up and destroyed by battle , or because their common effects were triggered , it is easy for them to accumulate such monsters in the GY . " Aztekipede , the Worm Warrior " and " Doom Dozer " can turn such cards into a utilizable resource by banishing them to facilitate their Special Summons . The latter also provides the Deck with a strong attacker to make up for most of the archetype ' s monsters having low ATK . The fact that the archetype ' s Flip monsters have low ATK and DEF can also be capitalized upon by including " Danipon " , " Gokipon " , and " Howling Insect " to the Deck , as all of them can be Set and easily destroyed by battle to search out the archetype ' s Flip monsters , with the latter two cards being able to search out any of those monsters . The first two cards are also Level 2 , allowing for synergy with " Shadow " or " Verdant Sanctuary " . " All - Out Attacks " is a useful option for the Deck in order to trigger the Flip effects of the archetype ' s monsters , by forcing the opponent to attack them . It can also be used in conjunction with " Shadow " to send the newly Summoned monsters to the GY , further disrupting the opponent ' s attempt to gain advantage .