Umi ( series ) " Umi " ( " Umi " ) is a series of cards focused around the Field Spell Card " Umi " . Playing style . A Legendary Ocean Deck . Numerous water decks rely on the Field Spell Card " A Legendary Ocean " to perform powerful effects as discussed below . Daedalus Method . One way to use " A Legendary Ocean " is with the " Levia - Dragon - Daedalus " or its superior , the " Ocean Dragon Lord - Neo - Daedalus " . Both monsters ' effects require " Umi " to be on the field ( which " A Legendary Ocean " is treated as ) . As a result , the entire field is destroyed except the " Daedalus " , leaving the user a clear field to perform direct attacks on the opponent . If " Abyssal Kingshark " is on the field when you activate the effect of " Daedalus " , the " Kingshark " is not destroyed . Normally , people would prefer " A Legendary Ocean " for this operation in contrast to " Umi " , because Summoning " Levia - Dragon - Daedalus " would only require one Tribute . Others prefer to use the card " Big Wave Small Wave " to Summon " Daedalus " , which is a smart addition to WATER Decks using these tactics . Another good idea is using " Warrior of Atlantis " to search out " A Legendary Ocean " . Decrease Level Method 1 . Another way to use " A Legendary Ocean " is to utilize its Level decreasing effect on WATER monsters on the field and in the hand . Strong Level 5 WATER monsters such as " Giga Gagagigo " , " Terrorking Salmon " , or " Catapult Turtle " can then be Normal Summoned without Tribute , allowing the user a more efficient way of bringing out monsters to inflict heavy damage . Decrease Level Method 2 . Another variation of this method utilizes stall cards such as " Gravity Bind " or " Level Limit - Area B " to halt monsters above Level 4 . Since the user ' s WATER monsters ( preferably monsters originally Level 4 ) are decreased in Level , then those monsters would be able to escape the stall cards . This allows " Mermaid Knight " or " Amphibious Bugroth MK - 3 " to either attack twice or attack directly . In the case of " Bugroth " , " Limiter Removal " can prove useful . " Field Barrier " will help in protecting " A Legendary Ocean " . Spell / Trap negation and / or removal will be handy as well , including " Dust Tornado " , " Twin Twisters " / " Mystical Space Typhoon " , or " Solemn Judgment " . " A Legendary Ocean " Decks to some extent can also utilize Synchro Monster s . " Deep Sea Diva " is a Tuner monster , and when Normal Summon ed it can bring out a Level 3 Sea Serpent - Type monster from your Deck , such as " Atlantean Pikeman " , " Mermaid Archer " , or " Spined Gillman " . This can allow a Level 4 or 5 Synchro Monster to be Summoned easily , although with " A Legendary Ocean " it will instead allow the Summoning of lower - Level Synchro Monsters . Additionally , " Deep Sea Diva " has less than 1500 ATK , so it can be added back to your hand by " Salvage " . " A Legendary Ocean " Decks to some extent can also utilize Xyz Monster s . Due to " A Legendary Ocean " lowering the Levels of WATER monsters , it is easy to Summon Rank 3 or lower Xyz Monsters , particularly WATER Xyz Monsters . Also , using original Level 5 WATER monsters whose Levels are lowered by " A Legendary Ocean " , such as " Giga Gagagigo " or " Terrorking Salmon " , allows the player to Summon Rank 4 Xyz Monsters , such as " Bahamut Shark " which can use its effect to Summon strong Rank 3 or lower WATER Xyz Monsters . Weaknesses . One weakness of this Deck is that in order for monsters to reach their full potential , they must have A Legendary Ocean or Umi on the field . This is easily remedied with cards such as Warrior of Atlantis . Another great weakness of this deck is Tualatin , as it can stop you from Summoning any monsters . Adding cards such as Horn of Heaven and Bottomless Trap Hole can help you overcome these hazards . These decks also function very slowly . So it is important to have cards against your opponent for decks that might be faster than you .