Locked in the Cemetery

Enchant creature
When this Aura enters, if there are five or more cards in your graveyard, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Lullmage Mentor

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.

Deeproot Pilgrimage

Whenever one or more nontoken Merfolk you control become tapped, create a 1/1 blue Merfolk creature token with hexproof.

Streambed Aquitects

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)
{T}: Target land becomes an Island until end of turn.

Elemental

Lord of Atlantis

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Founding the Third Path

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You may cast an instant or sorcery spell with mana value 1 or 2 from your hand without paying its mana cost.
II — Target player mills four cards.
III — Exile target instant or sorcery card from your graveyard. Copy it. You may cast the copy.

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Thada Adel, Acquisitor

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Thada Adel deals combat damage to a player, search that player's library for an artifact card and exile it. Then that player shuffles. Until end of turn, you may play that card.

Island

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Dramatic Reversal

Untap all nonland permanents you control.

Drowner of Secrets

Tap an untapped Merfolk you control: Target player mills a card.

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Serum Visions

Curate

Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Draw a card.

Merfolk Sovereign

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Expedition Lookout

Defender
As long as an opponent has eight or more cards in their graveyard, this creature can attack as though it didn't have defender and it can't be blocked.

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Eaten by Piranhas

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature loses all abilities and is a black Skeleton creature with base power and toughness 1/1. (It loses all other colors, card types, and creature types.)

Emperor Mihail II

You may look at the top card of your library any time.
You may cast Merfolk spells from the top of your library.
Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Tidal Courier

When this creature enters, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
{3}{U}: This creature gains flying until end of turn.

Seafloor Oracle

Whenever a Merfolk you control deals combat damage to a player, draw a card.

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

Sol Ring

Merrow Harbinger

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Harbinger of the Seas

Merrow Commerce

At the beginning of your end step, untap all Merfolk you control.

Thassa's Rebuff

Counter target spell unless its controller pays {X}, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Crashing Tide

This spell has flash as long as you control a Merfolk.
Return target creature to its owner's hand.
Draw a card.

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Rivendell

Rivendell enters tapped unless you control a legendary creature.
{T}: Add {U}.
{1}{U}, {T}: Scry 2. Activate only if you control a legendary creature.

Deeproot Waters

Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Merfolk

Mist Dancer

Flying
Other Merfolk you control get +1/+0 and have flying.
Encore {5}{U}{U} ({5}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Ertai's Scorn

This spell costs {U} less to cast if an opponent cast two or more spells this turn.
Counter target spell.

The Ring Tempts You

As the Ring tempts you, you get an emblem named The Ring if you don't have one. Then your emblem gains its next ability and you choose a creature you control to become or remain your Ring-bearer.
• The Ring can tempt you even if you don't control a creature.
• The Ring gains its abilities in order from top to bottom. Once it gains an ability, it has that ability for the rest of the game.
• Each time the Ring tempts you, you must choose a creature if you control one.
• Each player can have only one emblem named The Ring and only one Ring-bearer at a time.

The Ring

Your Ring-bearer is legendary and can't be blocked by creatures with greater power.
Whenever your Ring-bearer attacks, draw a card, then discard a card.
Whenever your Ring-bearer becomes blocked by a creature, that creature's controller sacrifices it at end of combat.
Whenever your Ring-bearer deals combat damage to a player, each opponent loses 3 life.

The Ring // The Ring Tempts You

Aetherize

Return all attacking creatures to their owner's hand.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Slinn Voda, the Rising Deep

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
When Slinn Voda enters, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Multiple Choice

If X is 1, scry 1, then draw a card.
If X is 2, you may choose a player. They return a creature they control to its owner's hand.
If X is 3, create a 4/4 blue and red Elemental creature token.
If X is 4 or more, do all of the above.

Silvergill Douser

{T}: Target creature gets -X/-0 until end of turn, where X is the number of Merfolk and/or Faeries you control.

Vodalian Hexcatcher

Flash
Other Merfolk you control get +1/+1.
Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Vodalian Arcanist

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

River's Rebuke

Return all nonland permanents target player controls to their owner's hand.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When this creature enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to this creature.

Coralhelm Commander

Level up {1} ({1}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 2-3
3/3
Flying
LEVEL 4+
4/4
Flying
Other Merfolk creatures you control get +1/+1.

Halimar Depths

This land enters tapped.
When this land enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Reliquary Tower

Merfolk Trickster

Flash
When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.

River Sneak

This creature can't be blocked.
Whenever another Merfolk you control enters, this creature gets +1/+1 until end of turn.

Cancel

Spellbook

Dispel

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Filter Out

Return all noncreature, nonland permanents to their owners' hands.

Glorious Gale

Counter target creature spell. If it was a legendary spell, the Ring tempts you.

Kopala, Warden of Waves

Spells your opponents cast that target a Merfolk you control cost {2} more to cast.
Abilities your opponents activate that target a Merfolk you control cost {2} more to activate.

Merfolk Spy

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature deals combat damage to a player, that player reveals a card at random from their hand.

Svyelun of Sea and Sky

Svyelun has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Council's Deliberation

Draw a card.
Whenever you scry, if you control an Island, you may exile this card from your graveyard. If you do, draw a card.

Consuming Tide

Each player chooses a nonland permanent they control. Return all nonland permanents not chosen this way to their owners' hands. Then you draw a card for each opponent who has more cards in their hand than you.

Harbinger of the Tides

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Coral Fighters

Whenever this creature attacks and isn't blocked, look at the top card of defending player's library. You may put that card on the bottom of that player's library.

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.