Gnawing Vermin

When Gnawing Vermin enters, target player mills two cards.
When Gnawing Vermin dies, target creature you don't control gets -1/-1 until end of turn.

Gollum's Bite

Target creature gets -2/-2 until end of turn.
{3}{B}, Exile Gollum's Bite from your graveyard: The Ring tempts you. Activate only as a sorcery.

Nasty End

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. If the sacrificed creature was legendary, draw three cards instead.

Door of Destinies

As Door of Destinies enters, 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.

Hero's Downfall

The Black Gate

As The Black Gate enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.
{1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.

Herald's Horn

As Herald's Horn enters, 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.

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Annihilating Glare

As an additional cost to cast this spell, pay {4} or sacrifice an artifact or creature.
Destroy target creature or planeswalker.

Marrow-Gnawer

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.

Nezumi Bladeblesser

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.)

The Dross Pits

The Dross Pits enters tapped.
{T}: Add {B}.
{1}{B}, {T}, Sacrifice The Dross Pits: Draw a card.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Lash of the Balrog

As an additional cost to cast this spell, sacrifice a creature or pay {4}.
Destroy target creature.

Offer Immortality

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Braids's Frightful Return

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 sacrifice a creature. If you do, each opponent discards a card.
II — Return target creature card from your graveyard to your hand.
III — Target opponent may sacrifice a nonland, nontoken permanent. If they don't, they lose 2 life and you draw a card.

Nezumi Prowler

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, target creature you control gains deathtouch and lifelink until end of turn.

Sol Ring

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Ossuary Rats

When Ossuary Rats enters, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Chittering Witch

When Chittering Witch enters, 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.

Vanquisher's Banner

As Vanquisher's Banner enters, 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.

Echo of Death's Wail

Flying, haste
When Echo of Death's Wail enters, gain control of all Rat tokens.
Whenever Echo of Death's Wail attacks, you may sacrifice another creature. If you do, draw a card.

Tribute to Horobi

(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.

Tribute to Horobi // Echo of Death's Wail

Wave of Rats

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.)

Shelob's Ambush

Target creature gets +1/+2 and gains deathtouch until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Ogre Slumlord

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

Ambition's Cost

You draw three cards and you lose 3 life.

Night's Whisper

Piper of the Swarm

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.

Vampiric Rites

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

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Dross Skullbomb

{1}, Sacrifice Dross Skullbomb: Draw a card.
{2}{B}, Sacrifice Dross Skullbomb: Return target creature card from your graveyard to your hand. Draw a card. Activate only as a sorcery.

Bitter Downfall

This spell costs {3} less to cast if it targets a creature that was dealt damage this turn.
Destroy target creature. Its controller loses 2 life.

Mukotai Ambusher

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

Thrumming Stone

Spells you cast have ripple 4. (Whenever you cast a spell, you may reveal the top four cards of your library. You may cast spells with the same name as that spell from among the revealed cards without paying their mana costs. Put the rest on the bottom of your library.)

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Swamp

Ashcoat of the Shadow Swarm

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.)

Path of Ancestry

Path of Ancestry enters 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.)

Icon of Ancestry

As Icon of Ancestry enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Horn of the Mark

Whenever two or more creatures you control attack a player, look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.