When Oblivion Ring enters, exile another target nonland permanent.

When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

, : Put a fate counter on target permanent.

, , Sacrifice Oblivion Stone: Destroy each nonland permanent without a fate counter on it, then remove all fate counters from all permanents.

Target creature you control gains indestructible until end of turn. Draw a card if that creature has a +1/+1 counter on it. (Damage and effects that say "destroy" don't destroy the creature.)

: Add .

: Return Oboro, Palace in the Clouds to its owner's hand.

Flying

: Obscura Initiate gains lifelink until end of turn.

When Obscura Polymorphist enters the battlefield, exile target creature. Its controller seeks a creature card.

If you control a commander, you may cast this spell without paying its mana cost.

Prevent all damage that would be dealt this turn by creatures your opponents control.

If it's neither day nor night, it becomes day as Obsessive Astronomer enters.

Whenever day becomes night or night becomes day, discard up to two cards, then draw that many cards.

Draw a card.

Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

: Draw a card, then discard a card.

, , Sacrifice Obsessive Stitcher: Return target creature card from your graveyard to the battlefield.

Protection from black

: Target creature gains protection from black until end of turn.

This spell costs less to cast for each land your opponents control that could produce .

Flying

When Obsidian Charmaw enters, destroy target nonbasic land an opponent controls.

When Obstinate Baloth enters, you gain 4 life.

If a spell or ability an opponent controls causes you to discard Obstinate Baloth, put it onto the battlefield instead of putting it into your graveyard.

Obstinate Gargoyle has flying as long as it's modified. (Equipment, Auras you control, and counters are modifications.)

Persist (When this creature 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.)

When Obzedat, Ghost Council enters, target opponent loses 2 life and you gain 2 life.

At the beginning of your end step, you may exile Obzedat. If you do, return it to the battlefield under its owner's control at the beginning of your next upkeep. It gains haste.

Draw X cards, then discard X cards. Create a 1/1 white Spirit creature token with flying for each card type among cards discarded this way.

Deathtouch

All creatures able to block Ochran Assassin do so.

: Regenerate Odious Trow.

When Odric, Blood-Cursed enters, create X Blood tokens, where X is the number of abilities from among flying, first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance found among creatures you control. (Count each ability only once.)

First strike (This creature deals combat damage before creatures without first strike.)

Whenever Odric, Master Tactician and at least three other creatures attack, you choose which creatures block this combat and how those creatures block.

When Odunos River Trawler enters, return target enchantment creature card from your graveyard to your hand.

, Sacrifice Odunos River Trawler: Return target enchantment creature card from your graveyard to your hand.

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

I — Put a +1/+1 counter on up to one target creature. Create a Food token.

II — Draw a card. Create a Food token.

III — Create a 1/1 white Halfling creature token for each Food you control.

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

This spell costs more to cast for each target beyond the first.

Choose any number of target players. Investigate X times, where X is the total number of creatures those players control.

At the beginning of your upkeep, look at the top two cards of your library, then put one of them into your graveyard.

Whenever a creature card is put into your graveyard from your library or hand, it perpetually gains "When this card leaves your graveyard, create a tapped 2/2 black Zombie creature token."

When Ogre Arsonist enters, destroy target land.

Menace

Whenever Ogre Chitterlord enters or attacks, create two 1/1 black Rat creature tokens with "This creature can't block." Then if you control five or more Rats, each Rat you control gets +2/+0 until end of turn.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

: Ogre Menial gets +1/+0 until end of turn.

: Destroy target creature that was dealt damage this turn.

Reach

Untap all Archers you control during each other player's untap step.

Whenever an Archer you control deals damage to a creature, you may pay . If you do, draw a card.

: Target snow creature gains first strike until end of turn. ( can be paid with one mana from a snow source.)

Trample

If a red source you control would deal an amount of noncombat damage less than Ojer Axonil's power to an opponent, that source deals damage equal to Ojer Axonil's power instead.

When Ojer Axonil dies, return it to the battlefield tapped and transformed under its owner's control.

Vigilance

If one or more creature tokens would be created under your control, three times that many of those tokens are created instead.

When Ojer Taq dies, return it to the battlefield tapped and transformed under its owner's control.

Whenever you cast a noncreature spell, choose one —

• Tap target creature.

• Ojutai Exemplars gains first strike and lifelink until end of turn.

• Exile Ojutai Exemplars, then return it to the battlefield tapped under its owner's control.

: Add or .

: Ojutai Monument becomes a 4/4 white and blue Dragon artifact creature with flying until end of turn.

Tap target creature. It doesn't untap during its controller's next untap step.

Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Create a 2/2 blue Djinn Monk creature token with flying.

Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Flying, trample

Whenever O-Kagachi, Vengeful Kami deals combat damage to a player, if that player attacked you during their last turn, exile target nonland permanent that player controls.

Return target creature or Vehicle card from your graveyard to the battlefield. Then put two +1/+1 counters on that permanent if you control an artifact and an enchantment.

As long as you have more cards in hand than each opponent, Okina Nightwatch gets +3/+3.

At the beginning of combat on your turn, Oko, the Ringleader becomes a copy of up to one target creature you control until end of turn, except he has hexproof.

+1: Draw two cards. If you've committed a crime this turn, discard a card. Otherwise, discard two cards.

−1: Create a 3/3 green Elk creature token.

−5: For each other nonland permanent you control, create a token that's a copy of that permanent.

+2: Create a Food token. (It's an artifact with ", , Sacrifice this artifact: You gain 3 life.")

+1: Target artifact or creature loses all abilities and becomes a green Elk creature with base power and toughness 3/3.

−5: Exchange control of target artifact or creature you control and target creature an opponent controls with power 3 or less.

Creatures you control have base power and toughness 3/3 until end of turn. You may search your library and/or graveyard for a card named Oko, the Trickster, reveal it, and put it into your hand. If you search your library this way, shuffle.

Flying

At the beginning of each end step, if a creature died this turn, create a Food token. (It's an artifact with ", , Sacrifice this artifact: You gain 3 life.")

, Sacrifice another creature or artifact: Old Flitterfang gets +2/+2 until end of turn.

When Old Rutstein enters and at the beginning of your upkeep, mill a card. If a land card is milled this way, create a Treasure token. If a creature card is milled this way, create a 1/1 green Insect creature token. If a noncreature, nonland card is milled this way, create a Blood token.

Flying

Old-Fashioned Vampire gets +2/+2 and has deathtouch as long as it's dark outdoors.

Flying

: Olivia Voldaren deals 1 damage to another target creature. That creature becomes a Vampire in addition to its other types. Put a +1/+1 counter on Olivia Voldaren.

: Gain control of target Vampire for as long as you control Olivia Voldaren.

Flying

Whenever another creature you control enters, you may discard a card. If you do, put a +1/+1 counter on that creature, it gains haste until end of turn, and it becomes a Vampire in addition to its other types.

Menace

Whenever Olivia's Attendants deals damage, create that many Blood tokens. (They're artifacts with ", , Discard a card, Sacrifice this artifact: Draw a card.")

: Olivia's Attendants deals 1 damage to any target.