msem-instigator

Undercroft Portal enters with four barrier counters on it.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, draw a card and remove a barrier counter from Undercroft Portal. Then if it has no barrier counters
on it, transform it.

Flash
If an opponent would draw a card, that player exiles the top card of their library instead. During each player's turn, that player may play that card for as long as it remains exiled.

Whenever a player casts a non-Dwarf spell or plays a non-Mountain land, this creature deals 2 damage to that player.
{1}{R}, Discard this card: Search your library for a Dwarf or Mountain card, reveal it, put it into your hand, then shuffle.

{T}: Add {C}.
{1}{R}, {T}, Discard a card: Exile the top card of your library. You may play it until the end of your next turn.
At the beginning of combat on your turn, if there are eight or more nonland cards in your graveyard, you may pay {2}{R}{R} and exile this land. When you do, it deals 5 damage to any target.

When this creature enters, search your library for a creature card with mana value 1 or less, reveal it, put it into your hand, then shuffle.
Arise {2}{W} ({2}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Vigilance
Whenever Underpass Sentinel enters or attacks, you may put a +1/+1 counter on another target creature you control without one.
Sacrifice Underpass Sentinel: Embattled creatures you control gain hexproof and indestructible until end of turn. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

At the beginning of your upkeep, reveal the top card of your library. If it has the same name as a card in your graveyard, put the revealed card into your hand. Otherwise, put it into your graveyard.

Archive 0 (As this enters, shuffle the top zero cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
As Undue's Study enters, shuffle your graveyard into the archived library.

[+2]: Exile up to three target cards from graveyards.
[+1]: Create a 2/1 black Horse Zombie creature token with lifelink.
[0]: If Undue has six or more loyalty counters on him, each opponent returns a creature card of their choice from a graveyard to the battlefield under your control.

When Undying Lich dies, create a 6/3 black Zombie Horror creature token with menace and “When this creature dies, create an 8/5 black Elder Demon Horror creature token with flying, deathtouch, and menace.”

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Unearthed Legion's power and toughness are each equal to the number of cards in your graveyard.
At the beginning of your upkeep, mill a card.

Whenever a creature you control dies, you may return all cards that were inscribed onto that creature and all Auras that were attached to that creature to their owners' hands.

Create three 1/1 colorless Servo artifact creature tokens.
Exile Unending Armies. At the beginning of your upkeep, if you have more life than each opponent, you may cast it without paying its mana cost. Otherwise, put it into your graveyard.

Enchant land
When Unexplored Regions enters, draw a card.
Enchanted land is an artifact in addition to its other types and has “{T}: Add one mana of any color.”

Whenever one or more creatures you control deal combat damage to a player, that player discards a card. Then that player may discard another card. If they don't, create two 2/1 black Nightmare creature tokens with “This creature can't block.”
Fleeting {1}{B}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Search your library for a card, reveal it, then shuffle and put that card on top of it. If you revealed a noncreature card this way, each opponent loses 2 life and you gain 2 life.

At the beginning of your upkeep, you may create a Treasure token. If you do, an opponent of your choice creates a tapped Treasure token.

If you would lose life, exile that many cards from the top of your library instead.
If you would gain life, draw that many cards instead.
When Unhallowed Concordat leaves the battlefield, you lose life equal to the number of cards you own in exile.

Destroy target creature with total power and toughness 8 or less.

{T}: Add one mana of any color.
{T}, Sacrifice Unicorn of the Vale: Add three mana of any one color.

Whenever you cast an enchantment spell, reveal the top card of your library. If it's an enchantment card, you may put it onto the battlefield.

If you would draw a card, you may return an instant or sorcery card from your graveyard to your hand instead.
{U}: Draw three cards.

Whenever you cast a noncreature spell, create a 1/1 colorless Construct artifact creature token.

When Unite Against Evil enters, return target creature card with mana value 3 or less from your graveyard to the battlefield.
Menagerie — Whenever you attack, if there are five or more creature types among creatures you control, put a +1/+1 counter on target attacking creature and untap it.