Aqua / Effect

(Quick Effect): You can discard this card, then target 1 WATER monster you control; destroy 1 other WATER monster in your hand or field, and if you do, the targeted monster gains ATK/DEF equal to the destroyed monster's original ATK/DEF, until the end of this turn. If this card is sent from the field to the GY: You can draw 1 card, then discard 1 card. You can only use each effect of "Mermail Abyssnerei" once per turn.

Fish / Effect

When this card destroys an opponent's monster by battle and sends it to the Graveyard: You can discard 1 WATER monster to the Graveyard; Special Summon 1 "Mermail" monster from your Deck in face-up Defense Position. You can only use the effect of "Mermail Abyssnose" once per turn.

Aqua / Effect

You can target 1 "Mermail" monster you control; Special Summon any number of Level 4 or lower "Mermail" monsters from your Deck whose combined Levels are less than or equal to the Level of that monster, then send that monster to the Graveyard. You can only use the effect of "Mermail Abyssocea" once per turn.

Fish / Effect

When this card is Normal or Special Summoned: You can discard 1 WATER monster to the Graveyard; add 1 Level 3 WATER monster from your Deck to your hand. You can only use this effect of "Mermail Abysspike" once per turn.

Aqua / Effect

You can discard 1 other WATER monster to the GY; Special Summon this card from your hand. When Summoned this way: You can add 1 Level 4 or lower "Mermail" monster from your Deck to your hand. You can only use this effect of "Mermail Abyssteus" once per turn.

Sea Serpent / Xyz / Effect

3 Level 3 monsters

During either player's turn, when your opponent targets exactly 1 face-up "Mermail" monster you control for an attack, or with a Spell/Trap effect that could have targeted this card (except during the Damage Step): You can detach 1 Xyz Material from this card; that attack/effect now targets this card. When this card is destroyed and sent to the Graveyard: You can target 1 "Mermail" monster in your Graveyard, except "Mermail Abysstrite"; Special Summon that target.

Fish / Effect

When this card is Normal or Special Summoned: You can discard 1 WATER monster to the Graveyard, then target 1 Level 3 or lower WATER monster in your Graveyard; add that target to your hand. You can only use the effect of "Mermail Abyssturge" once per turn.

Beast / Synchro / Effect

1 Tuner + 1+ non-Tuner monsters

If this card is Special Summoned: You can target 1 face-up monster on the field; return it to the hand. If your opponent Normal or Special Summons a monster(s) (except during the Damage Step), or if an opponent's monster targets this card for an attack: You can return this card to the Extra Deck, then, you can Special Summon 1 "Melffy" Xyz Monster from your Extra Deck. You can only use each effect of "Merry Melffys" once per turn.

During your opponent's next turn after you activate this card, your opponent cannot change the battle positions of monsters, except with a card effect.

Target 3 monsters with different Levels in your Graveyard; Special Summon all 3 of them. Their ATK's become 0, also their effects are negated. If you do not Xyz Summon this turn after Summoning those 3 monsters, you lose 4000 Life Points during the End Phase. You cannot Special Summon any other monsters, except by Xyz Summon, during the turn you activate this card.

Monsters with 1500 or more ATK cannot declare an attack. Once per turn, during your Standby Phase, pay 100 LP or destroy this card.

Fiend / Effect

When you Tribute this card for the Tribute Summon of a DARK monster, Special Summon 3 "Metabo Tokens" (Fiend-Type/DARK/Level 1/ATK 0/DEF 0) in Defense Position. These tokens cannot be Tributed for a Tribute Summon.

Fish / Effect

When this card is Normal Summoned: You can target 2 Fish-Type monsters in your Graveyard; shuffle those targets into your Deck.

Fairy / Effect

Cannot be Special Summoned from the Deck. If you control no monsters, you can Normal Summon this card without Tributing. Cannot be destroyed by battle or card effects. You take no battle damage from attacks involving this Attack Position card. At the end of the Battle Phase, if this card battled: Return as many monsters on the field as possible to the hand (other than this card), and if you do, inflict 300 damage to your opponent for each card returned. Once per turn, during your Standby Phase: Shuffle this card into the Deck.

Insect / Normal

A gigantic insect-like creature covered by thick armor. Everything in his path is destroyed.

You can activate this card when a Continuous Trap Card is activated. Negate all Continuous Trap Cards during the turn this card is activated.

Machine / Fusion

"Steel Ogre Grotto #1" + "Lesser Dragon"

Machine / Normal

A metal fish with a razor-sharp caudal fin.

Fiend

A fiend guarding the treasures of the netherworld, it's most at home in the dark.

Special Summon this card in Defense Position as an Effect Monster (Aqua/WATER/Level 10/ATK 0/DEF 3000). (This card is also still a Trap.) If Summoned this way, this card cannot attack.

Machine / Effect

When this card is Normal Summoned, place 2 counters on it. This card gains 800 ATK for each of these counters on it. If this card would be destroyed by a card effect, remove 1 of this card's counters instead.

Psychic / Fusion

1 "Metalfoes" monster + 1 monster with 2500 or less ATK

Once per turn, if a Fusion Monster is Fusion Summoned: You can target 1 "Metalfoes" monster in your GY with a lower Level than that Fusion Monster; Special Summon it. If this card is sent from the field to the GY: You can add 1 "Metalfoes" monster from your Deck to your hand.

If a card(s) you control is destroyed by battle or card effect: Special Summon 1 "Metalfoes" monster from your Deck. During either player's turn, except the turn this card was sent to the GY: You can banish this card from your GY; add 1 face-up "Metalfoes" Pendulum Monster from your Extra Deck to your hand.

Psychic / Fusion

1 "Metalfoes" monster + 2 monsters with 3000 or less ATK