msem-instigator

Whenever Desperate Thief deals combat damage to a player, you may pay 2 life. If you do, draw a card.

As an additional cost to cast this spell, pay {2} or sacrifice a creature.
Flying, vigilance

Haste
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever a creature you control assaults, you may have target creature get -2/-2 until end of turn.

Flying
Whenever another creature dies, each opponent loses 1 life and you gain 1 life.

Rapport — Whenever Desraen, Serpent's Will and at least one other creature you control become tapped, you may cast target instant or sorcery card with mana value 3 or less from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Whenever you create one or more tokens, put a rift counter on Destabilizing the Rifts.
As long as Destabilizing the Rifts has seven or more rift counters on it, creature tokens you control can't leave the battlefield.

When Destiny Beyond Measure enters, tap each creature you control.
Creatures you control get +8/+8 and have “This creature enters tapped.”

As Destroyed Isle enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {W}, {U}, or {B}.

{2}, {T}: Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step. Activate only as a sorcery.

Archive 4 (As this enters, shuffle the top four cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
At the beginning of each opponent's upkeep, that player may pay 2 life. If they do, you gain 2 life. Otherwise, you draw a card from the archived library.

Trample
Creatures your opponents control get -1/-0.

Flying
Whenever you cast your second spell each turn, put a +1/+1 counter on Detached Specters.

Whenever one or more creatures you control deal combat damage to a player or planeswalker, you draw a card and you lose 1 life.

Determined Chevalier has vigilance as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Tithe (When this creature enters, you may tap three other artifacts and/or creatures you control.)
Menace, lifelink
When Determined Evangelist's tithe is paid, put two +1/+1 counters on it.

Menace
{1}{B}, Exile another three cards from your graveyard: Return Determined Explorer from your graveyard to your hand.

Whenever Determined Hero attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Determined Koi has three or more +1/+1 counters on it, remove them all and transform it.

{2}{B}, Sacrifice Determined Slayer: Exile up to three target cards from target player's graveyard. They lose that much life.

Whenever Determined to Prevail or another artifact or enchantment you control enters, target creature you control gets +1/+1 and gains indestructible and vigilance until end of turn.

When Detritus Scourge enters, you mill eight cards. Put a +1/+1 counter on Detritus Scourge for each creature card milled this way.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Devilish Undoer enters, if the trial was failed, return target creature card from your graveyard to your hand.

Menace
When Devious Kalku enters, you may search your library for a card, put that card into your graveyard, then shuffle.

Flash
When Devious Naiad enters, exchange control of it and target creature until end of turn. Untap that creature. It gains haste until end of turn.