msem-instigator

{T}, Sacrifice a permanent: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

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.

{6}{W}: Tap all creatures target player controls.

Gain control of target creature until end of turn. Untap that creature. It gains haste and is marked until end of turn.

All creatures have “When this creature enters, destroy target creature with a lesser mana value.”

{4}{B}{B}: Return Urchin Defector from your graveyard to the battlefield transformed.

Menace

Target creature gets +2/+2 and gains indestructible until end of turn.

Hexproof
As long as an opponent controls a permanent you own, Vault Sentinel gets +4/+4.

Whenever you cast a spell during an opponent's turn, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
Whenever a creature you control enters, each opponent loses 1 life.
I, II — Create a 1/1 black Actor creature token with lifelink.
III — Each opponent loses life equal to the number of tokens you control. You gain life equal to the life lost this way.

Whenever you sacrifice a Clue, Vivian's Vanguard gets +2/+0 and gains flying until end of turn.

[+1]: Exile up to one other target permanent until the beginning of its owner's next end step.
[–1]: Return another target planeswalker to its owner's hand.
[–6]: You get an emblem with “Whenever a permanent leaves the battlefield, each opponent discards a card.”

Target creature gets +X/+X and gains vigilance until your next turn, where X is the number of creatures you control.

{5}, {T}, Sacrifice Voidlife Orbs: Destroy all nonland permanents. You can't spend more than one color of mana to activate this ability.

When Walking Armory enters, return all Equipment cards from your graveyard to the battlefield, then attach them to Walking Armory.

Create X 1/1 white Spirit creature tokens with flying, where X is two plus the number of cards named Wandering Souls in your graveyard. Conjure three cards named Wandering Souls and shuffle them into your main library.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — War's Sorrow deals 1 damage to any target.
III — Each player sacrifices another permanent. Put War's Sorrow on top of its owner's library unless a player has it deal 3 damage to them.

Equipped creature gets +2/+2 and has haste and trample.
Whenever another creature you control dies, sacrifice equipped creature.
Equip {1}

Each creature with power greater than its toughness doesn't untap during its controller's untap step.

You may put a Dragon creature card from your hand onto the battlefield. That creature gains haste until end of turn. Return it to its owner's hand at the beginning of the next end step.

When Wayfaring Realmstitcher enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Whenever a creature you control enters from a graveyard, target opponent loses life equal to its power.

Creatures can't attack or block alone.

{T}: Add {C}.
{9}, {T}, Exile Whiterun Gates: Take an extra turn after this one.