Whenever Ashcoat of the Shadow Swarm attacks or blocks, other Rats you control get +X/+X until end of turn, where X is the number of Rats you control.

At the beginning of your end step, you may mill four cards. If you do, return up to two Rat creature cards from your graveyard to your hand. (To mill a card, put the top card of your library into your graveyard.)

Changeling (This card is every creature type.)

As Bloodline Pretender enters the battlefield, choose a creature type.

Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Black creature spells you cast cost {1} less to cast.

Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Haste

Menace (This creature can't be blocked except by two or more creatures.)

When Chittering Host enters the battlefield, other creatures you control get +1/+0 and gain menace until end of turn.

When Chittering Rats enters the battlefield, target opponent puts a card from their hand on top of their library.

When Chittering Witch enters the battlefield, create a number of 1/1 black Rat creature tokens equal to the number of opponents you have.

{1}{B}, Sacrifice a creature: Target creature gets -2/-2 until end of turn.

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

As an additional cost to cast this spell, sacrifice a creature.

Draw two cards.

Defender

{T}: Creatures you control gain haste until end of turn.

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Add {B}{B}{B}.

Target creature gets -1/-1 until end of turn for each Swamp you control.

Search your library for a card, put that card into your hand, then shuffle.

As Door of Destinies enters the battlefield, choose a creature type.

Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.

Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.

Exile target creature or planeswalker.

Creatures you control get +1/+1 and have flying and indestructible.

At the beginning of your upkeep, sacrifice a creature. If you can't, sacrifice Eldrazi Monument.

Everglades enters the battlefield tapped.

When Everglades enters the battlefield, sacrifice it unless you return an untapped Swamp you control to its owner's hand.

{T}: Add {C}{B}.

Target opponent loses 1 life for each attacking creature you control. You gain that much life.

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Changeling (This card is every creature type.)

When Graveshifter enters the battlefield, you may return target creature card from your graveyard to your hand.

Each opponent loses 1 life for each creature you control.

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Choose a creature type. Return up to two creature cards of that type from your graveyard to the battlefield. If this spell was foretold, return all creature cards of that type from your graveyard to the battlefield instead.

Foretell {5}{B}{B} (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.)

As Herald's Horn enters the battlefield, choose a creature type.

Creature spells you cast of the chosen type cost {1} less to cast.

At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

As Heraldic Banner enters the battlefield, choose a color.

Creatures you control of the chosen color get +1/+0.

{T}: Add one mana of the chosen color.

Ninjutsu {3}{B}{B} ({3}{B}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever Ink-Eyes, Servant of Oni deals combat damage to a player, you may put target creature card from that player's graveyard onto the battlefield under your control.

{1}{B}: Regenerate Ink-Eyes.

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

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

{1}{B}: Regenerate Kuro's Taken.

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.

-3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.

-6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

All Rats have fear.

{T}, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.

When Midnight Scavengers enters the battlefield, you may return target creature card with mana value 3 or less from your graveyard to your hand.

(Melds with Graf Rats.)

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Lifelink

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever Nashi, Moon Sage's Scion deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Nezumi Bladeblesser has deathtouch as long as you control an artifact.

Nezumi Bladeblesser has menace as long as you control an enchantment. (It can't be blocked except by two or more creatures.)

{B}, Sacrifice a creature: Target player discards a card. Activate only as a sorcery.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Nezumi Cutthroat can't block.

{1}{B}: Exile target card from an opponent's graveyard. If no cards are in that graveyard, flip Nezumi Graverobber.

{4}{B}: Put target creature card from a graveyard onto the battlefield under your control.

When Nezumi Informant enters the battlefield, each opponent discards a card.

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

When Nezumi Prowler enters the battlefield, target creature you control gains deathtouch and lifelink until end of turn.

Nyx Lotus enters the battlefield tapped.

{T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.

Rats you control have deathtouch.

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever Okiba-Gang Shinobi deals combat damage to a player, that player discards two cards.

Pack Rat's power and toughness are each equal to the number of Rats you control.

{2}{B}, Discard a card: Create a token that's a copy of Pack Rat.

Path of Ancestry enters the battlefield tapped.

{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

{T}: Add one mana of any color.

{1}, {T}: Untap target legendary creature you control.

Rat offering (You may cast this card any time you could cast an instant by sacrificing a Rat and paying the difference in mana costs between this and the sacrificed Rat. Mana cost includes color.)

Whenever a permanent is put into an opponent's graveyard, that player loses 1 life.

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

At the beginning of your upkeep, you draw a card and you lose 1 life.

Rats you control have menace.

{1}{B}, {T}: Create a 1/1 black Rat creature token.

{2}{B}{B}, {T}, Sacrifice three Rats: Gain control of target creature.

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way.

You draw a card and you lose 1 life.

Rat Colony gets +1/+0 for each other Rat you control.

A deck can have any number of cards named Rat Colony.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

At the beginning of your upkeep, you may search your library for a Rat card, reveal it, put it into your hand, then shuffle.

You have no maximum hand size.

{T}: Add {C}.

{T}: Add {C}.

{4}, {T}: Target creature can't be blocked this turn.

Deathtouch

When Ruin Rat dies, exile target card from an opponent's graveyard.

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

As long as Sinuous Vermin is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Equipped creature gets +1/-1.

Whenever equipped creature dies, draw two cards.

Equip {1}

Ninjutsu {B} ({B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever Skullsnatcher deals combat damage to a player, exile up to two target cards from that player's graveyard.

{T}: Add {C}{C}.

As Species Specialist enters the battlefield, choose a creature type.

Whenever a creature of the chosen type dies, you may draw a card.

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.

Equip {2}

Shadow (This creature can block or be blocked by only creatures with shadow.)

Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

Swarm of Rats's power is equal to the number of Rats you control.

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever Throat Slitter deals combat damage to a player, destroy target nonblack creature that player controls.

Target creature gets -1/-1 until end of turn.

Morbid -- That creature gets -13/-13 until end of turn instead if a creature died this turn.

(As this Saga enters and after your draw step, add a lore counter.)

I, II -- Each opponent creates a 1/1 black Rat Rogue creature token.

III -- Exile this Saga, then return it to the battlefield transformed under your control.

Flying, haste

When Echo of Death's Wail enters the battlefield, gain control of all Rat tokens.

Whenever Echo of Death's Wail attacks, you may sacrifice another creature. If you do, draw a card.

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

As Vanquisher's Banner enters the battlefield, choose a creature type.

Creatures you control of the chosen type get +1/+1.

Whenever you cast a creature spell of the chosen type, draw a card.

As an additional cost to cast this spell, sacrifice a creature.

Draw two cards.

Trample

When Wave of Rats dies, if it dealt combat damage to a player this turn, return it to the battlefield under its owner's control.

Blitz {4}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Creatures you control have lifelink.

{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.