Umi Control Deck Breakdown
Main Deck
Electric Jellyfish
ATK:
1400
DEF:
1700
You can send 1 "Umi" from your hand, Deck, or face-up field to the GY; Special Summon 1 WATER monster from your hand. When your opponent activates a monster effect, or Spell Card or effect, while "Umi" is on the field (Quick Effect): You can negate that effect, then, you can make this card gain 600 ATK/DEF. You can only use each effect of "Electric Jellyfish" once per turn.
Mega Fortress Whale
ATK:
2550
DEF:
2350
If "Umi" is on the field: You can activate this effect; your WATER monsters can attack directly this turn. During your opponent's Battle Phase (Quick Effect): You can target 1 face-up monster your opponent controls; destroy it. If this card on the field is destroyed by battle or card effect: You can either add to your hand or Special Summon 1 WATER Warrior monster from your Deck or GY. You can only use each effect of "Mega Fortress Whale" once per turn.
Ocean Dragon Lord - Kairyu-Shin
ATK:
2000
DEF:
1700
While "Umi" is on the field, each player can only control 1 face-up non-WATER monster. (If a player controls 2 or more, they must send some to the GY so they only control 1.) During your Main Phase: You can add from your Deck to your hand 1 "Umi", 1 "Kairyu-Shin" Spell/Trap, or 1 "Sea Stealth" Spell/Trap. You can only use this effect of "Ocean Dragon Lord - Kairyu-Shin" once per turn.
Sea Stealth II
This card's name becomes "Umi" while on the field or in the GY. Your opponent cannot target WATER monsters you control with non-WATER monster effects. At the start of the Battle Phase: You can Special Summon from your hand or GY, 1 monster that mentions "Umi", or 1 WATER Normal Monster, in Defense Position, but destroy it at the end of the Battle Phase. You can only use this effect of "Sea Stealth II" once per turn.
Sea Stealth Attack
When this card is activated: You can activate 1 "Umi" from your hand or GY. While "Umi" is on the field, this face-up card gains these effects. ● Once per turn: You can banish 1 WATER monster you control until the End Phase; this turn, face-up Spells/Traps you control cannot be destroyed by your opponent's card effects (even if this card leaves the field). ● At the start of the Damage Step, if your WATER monster whose original Level is 5 or higher battles an opponent's monster: Destroy that opponent's monster.
Main: 42 Extra: 15
Electric Jellyfish
ATK:
1400
DEF:
1700
You can send 1 "Umi" from your hand, Deck, or face-up field to the GY; Special Summon 1 WATER monster from your hand. When your opponent activates a monster effect, or Spell Card or effect, while "Umi" is on the field (Quick Effect): You can negate that effect, then, you can make this card gain 600 ATK/DEF. You can only use each effect of "Electric Jellyfish" once per turn.
Gameciel, the Sea Turtle Kaiju
ATK:
2200
DEF:
3000
You can Special Summon this card (from your hand) to your opponent's field in Attack Position, by Tributing 1 monster they control. If your opponent controls a "Kaiju" monster, you can Special Summon this card (from your hand) in Attack Position. You can only control 1 "Kaiju" monster. When your opponent activates a card or effect, except "Gameciel, the Sea Turtle Kaiju" (Quick Effect): You can remove 2 Kaiju Counters from anywhere on the field; negate the activation, and if you do, banish that card.
Mega Fortress Whale
ATK:
2550
DEF:
2350
If "Umi" is on the field: You can activate this effect; your WATER monsters can attack directly this turn. During your opponent's Battle Phase (Quick Effect): You can target 1 face-up monster your opponent controls; destroy it. If this card on the field is destroyed by battle or card effect: You can either add to your hand or Special Summon 1 WATER Warrior monster from your Deck or GY. You can only use each effect of "Mega Fortress Whale" once per turn.
Ocean Dragon Lord - Kairyu-Shin
ATK:
2000
DEF:
1700
While "Umi" is on the field, each player can only control 1 face-up non-WATER monster. (If a player controls 2 or more, they must send some to the GY so they only control 1.) During your Main Phase: You can add from your Deck to your hand 1 "Umi", 1 "Kairyu-Shin" Spell/Trap, or 1 "Sea Stealth" Spell/Trap. You can only use this effect of "Ocean Dragon Lord - Kairyu-Shin" once per turn.
Sea Stealth II
This card's name becomes "Umi" while on the field or in the GY. Your opponent cannot target WATER monsters you control with non-WATER monster effects. At the start of the Battle Phase: You can Special Summon from your hand or GY, 1 monster that mentions "Umi", or 1 WATER Normal Monster, in Defense Position, but destroy it at the end of the Battle Phase. You can only use this effect of "Sea Stealth II" once per turn.
Small World
Reveal 1 monster in your hand, choose 1 monster from your Deck that has exactly 1 of the same Type, Attribute, Level, ATK or DEF, and banish the revealed monster from your hand face-down. Then add, from the Deck to your hand, 1 monster that has exactly 1 of the same Type, Attribute, Level, ATK or DEF as the monster chosen from your Deck, and banish the card chosen from the Deck face-down. You can only activate 1 "Small World" per turn.
Kairyu-Shin's Dark Reef
Send 1 face-up "Umi" you control to the GY; Special Summon up to 2 monsters with different names from your hand and/or Deck, that mention "Umi" or are WATER Normal Monsters, in Defense Position, then if your opponent controls a monster, you can Special Summon any number of Level 6 or lower WATER Normal Monsters from your hand and/or Deck. Until the end of your next turn after this card resolves, you cannot Special Summon monsters, except WATER monsters. You can only activate 1 "Kairyu-Shin's Dark Reef" per turn.
Sea Stealth Attack
When this card is activated: You can activate 1 "Umi" from your hand or GY. While "Umi" is on the field, this face-up card gains these effects. ● Once per turn: You can banish 1 WATER monster you control until the End Phase; this turn, face-up Spells/Traps you control cannot be destroyed by your opponent's card effects (even if this card leaves the field). ● At the start of the Damage Step, if your WATER monster whose original Level is 5 or higher battles an opponent's monster: Destroy that opponent's monster.
Trap Trick
Banish 1 Normal Trap from your Deck, except "Trap Trick", and Set 1 card with the same name directly from your Deck, also it can be activated this turn. You can only activate 1 Trap Card for the rest of this turn after this card resolves. You can only activate 1 "Trap Trick" per turn.
I:P Masquerena
ATK:
800
LINK-2
Link Arrow:
Bottom-Left
Bottom-Right
2 non-Link Monsters During your opponent's Main Phase, you can (Quick Effect): Immediately after this effect resolves, Link Summon 1 Link Monster using materials you control, including this card. You can only use this effect of "I:P Masquerena" once per turn. A Link Monster that used this card as material cannot be destroyed by your opponent's card effects.
Knightmare Phoenix
ATK:
1900
LINK-2
Link Arrow:
Top
Right
2 monsters with different names If this card is Link Summoned: You can discard 1 card, then target 1 Spell/Trap your opponent controls; destroy it, then, if this card was co-linked when this effect was activated, you can draw 1 card. You can only use this effect of "Knightmare Phoenix" once per turn. Co-linked monsters you control cannot be destroyed by battle.
Linguriboh
ATK:
300
LINK-1
Link Arrow:
Bottom-Left
1 Level 4 or lower Cyberse monster When your opponent activates a Trap Card (Quick Effect): You can Tribute this card; negate that card's effect, and if you do, banish it. If this card is in your GY (Quick Effect): You can Tribute 1 "@Ignister" monster that was Summoned from the Extra Deck; Special Summon this card. You can only use each effect of "Linguriboh" once per turn.
Mekk-Knight Crusadia Avramax
ATK:
3000
LINK-4
Link Arrow:
Left
Right
Bottom-Left
Bottom-Right
2+ monsters Special Summoned from the Extra Deck While this Link Summoned card is on the field, your opponent cannot target this card with card effects, also their monsters cannot target monsters for attacks, except this one. Once per battle, during damage calculation, if this card battles a Special Summoned monster (Quick Effect): You can make this card gain ATK equal to that opponent's monster's ATK during that damage calculation only. If this Link Summoned card you control is sent to your GY by an opponent's card: You can shuffle 1 card on the field into the Deck.
Relinquished Anima
ATK:
0
LINK-1
Link Arrow:
Top
1 Level 1 monster, except a Token You can target 1 face-up monster this card points to; equip that face-up monster to this card (max. 1). You can only use this effect of "Relinquished Anima" once per turn. This card gains ATK equal to that equipped monster's.
S:P Little Knight
ATK:
1600
LINK-2
Link Arrow:
Left
Right
2 Effect Monsters If this card is Link Summoned using a Fusion, Synchro, Xyz, or Link Monster as material: You can target 1 card on the field or in either GY; banish it, also your monsters cannot attack directly this turn. When your opponent activates a card or effect (Quick Effect): You can target 2 face-up monsters on the field, including a monster you control; banish both until the End Phase. You can only use each effect of "S:P Little Knight" once per turn.
Underworld Goddess of the Closed World
ATK:
3000
LINK-5
Link Arrow:
Top
Top-Right
Right
Bottom
Bottom-Right
4+ Effect Monsters You can also use 1 monster your opponent controls as material to Link Summon this card. If this card is Link Summoned: You can negate the effects of all face-up monsters your opponent currently controls. This Link Summoned card is unaffected by your opponent's activated effects, unless they target this card. Once per turn, when your opponent activates a card or effect that Special Summons a monster(s) from the GY (Quick Effect): You can negate the activation.
Divine Arsenal AA-ZEUS - Sky Thunder
ATK:
3000
DEF:
3000
2 Level 12 monsters Once per turn, if an Xyz Monster battled this turn, you can also Xyz Summon "Divine Arsenal AA-ZEUS - Sky Thunder" by using 1 Xyz Monster you control as material. (Transfer its materials to this card.) (Quick Effect): You can detach 2 materials from this card; send all other cards from the field to the GY. Once per turn, if another card(s) you control is destroyed by battle or an opponent's card effect: You can attach 1 card from your hand, Deck, or Extra Deck to this card as material.
Number 41: Bagooska the Terribly Tired Tapir
ATK:
2100
DEF:
2000
2 Level 4 monsters Once per turn, during your Standby Phase, detach 1 material from this card. If you cannot, destroy it. This Attack Position card cannot be destroyed by your opponent's card effects. Your opponent cannot target this Attack Position card with card effects. While this card is in face-up Defense Position, change all face-up monsters on the field to Defense Position, also negate the activated effects of monsters that were in Defense Position when that effect was activated.
Super Starslayer TY-PHON - Sky Crisis
ATK:
2900
DEF:
2900
2 Level 12 monsters During the turn, or turn after, your opponent Special Summoned 2 or more monsters from the Extra Deck, you can also Xyz Summon this card by using 1 monster you control with the highest ATK (your choice, if tied). (Transfer its materials to this card.) If you do, you cannot Normal or Special Summon monsters for the rest of this turn. While this Xyz Summoned monster is on the field, neither player can activate the effects of monsters with 3000 or more ATK. Once per turn: You can detach 1 material from this card; return 1 monster from the field to the hand.
Tri-Edge Levia
ATK:
1800
DEF:
1500
3 Level 3 monsters Banish any monster destroyed by battle with this card. Once per turn, during either player's turn: You can detach 1 Xyz Material from this card, then target 1 face-up monster on the field; it loses 800 ATK, also its effects are negated. These changes last until the end of this turn.