msem-instigator

Prowess
Whenever Prodigal Spark is dealt damage, it deals that much damage to any target.

Flying, haste
Whenever Pyrus, the Undying Flame attacks, add {R}{R}{R}{R}. You don't lose this mana as steps, phases, and turns end.
{1}{R}: Pyrus gets +1/+0 until end of turn.

Whenever you cast a noncreature spell, Rageborn Pyromancer gets +1/+1 until end of turn.
{1}{R}: Rageborn Pyromancer gets +1/+0 and gains flying until end of turn.

Haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Rahstahde's Firefist. It gains menace until end of turn.

Whenever you cast an instant or sorcery spell, put a loyalty counter on Reytali of Endless Muses.
[0]: Add X mana in any combination of colors, where X is the number of spells you've cast this turn.
[–3]: Create two 3/1 red Sand creature tokens with haste.

(Transform this if it's not attached to a creature. Pay {1}{R} as a sorcery to unattach it.)
Enchant creature you control
Scale Bearer's rider gets +4/+3 and has flying and haste.
Whenever Scale Bearer's rider attacks, you may pay {2}{R}. If you do, it deals damage equal to its power to target creature or planeswalker.

Enchant player
Whenever enchanted player taps a nonbasic land they control, that land doesn't untap during its controller's next untap step.

Double strike
Creatures you control have trample.
Excess noncombat damage that would be dealt by sources you control to permanents an opponent controls is dealt to that player instead.

Creatures your opponents control can't block alone. (They can block different creatures.)

Double strike
At the beginning of each end step, if a creature you control died this turn, Tempered Survivor deals 2 damage to each opponent.

Flying, haste
Whenever The Branded Usurper attacks, it deals 2 damage to any target.
If you would lose the game, instead exile The Branded Usurper. Your life total becomes 0. Until an opponent's next turn, you can't lose the game and you can't gain life. Take an extra turn after this one.

Indestructible
At the beginning of your upkeep or when this creature transforms into The Divine Lovers, gain control of target permanent with mana value X or less until end of turn, where X is the number of creatures you control. Untap that permanent. It gains haste until end of turn.