msem-instigator

When you cast Senaturian Centurion, reveal cards from the top of your library until you reveal a creature card with mana value 2 or less. Copy that card, then put the revealed card into your hand. You may cast the copy without paying its mana cost. Put the revealed cards on the bottom of your library in a random order.

Senaturian Legion gets +1/+1 for each other creature on the battlefield named Senaturian Legion.
A deck can have any number of cards named Senaturian Legion.

When Sending Stones enters, harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)
If you would harmonize, you may trigger a harmony of a permanent card in your graveyard instead.

Choose one —
• Target permanent gains protection from instants and sorceries until end of turn.
• You gain 3 life.
• Draw a card.

Equipped creature gets +2/+0. As long as it's a Knight, it has first strike.
Equip {1}{W}

Whenever Sentry of Kollis Gate is dealt damage, put a +1/+1 counter on each other creature you control.

Flying, vigilance
Whenever Sepulchral Guide attacks, prevent all combat damage that would be dealt to another target creature you control this turn. If that creature has two or more counters on it, untap it.

Flying
When Seraph of Renewal leaves the battlefield, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Flying, vigilance, lifelink
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.)

Flying
Whenever you cycle Seraph of the Stage or it attacks, audition for white. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Cleric Role giving 2/2 and lifelink. Roles replace older ones.)
Basic landcycling {1}{W} ({1}{W}, Discard this card: Search your library for a basic land card, reveal it, and put it into your hand, then shuffle.)

Prevent all damage target spell or permanent would deal this turn. You gain life equal to the damage prevented this way.

Vanishing 10 (This permanent enters with ten time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
If you would lose 1 or more life other than to pay a cost, instead remove that many time counters from Serene Prayer. (If you would lose more life than there are time counters on Serene Prayer, the life loss is still prevented.)

Enchant creature
Enchanted creature can't attack.
Civilized — Enchanted creature can't block and its activated abilities can't be activated if you control an artifact, a creature, and an enchantment.

[+1]: Distribute two +1/+1 counters among any number of target creatures you control.
[–1]: Create two 1/1 white Monk creature tokens.
[–6]: Until your next turn, you choose which creatures attack or block and how those creatures attack or block.

[+1]: Create a 1/1 white Warrior creature token with lifelink. You gain 1 life.
[–2]: Put two +1/+1 counters on target creature. It gains double strike until end of turn.
[–7]: Choose up to three creatures, then destroy the rest.

As long as it's your turn, Seto San is a 3/3 Human Warrior creature with indestructible.
[+1]: Up to one target creature you control gains lifelink until end of turn.
[0]: Create a 1/1 white Warrior creature token.
[–X]: Search your library for an Aura or Equipment card with mana value X and put it onto the battlefield, then shuffle.

[+1]: Create two 1/1 white Warrior creature tokens. You gain 2 life.
[–2]: Destroy each creature with the greatest power or tied for the greatest power among creatures on the battlefield.
[–5]: Creatures you control get +X/+X and gain lifelink until end of turn, where X is the number of creatures you control.

Destroy all creatures.

Enchant player
At the beginning of enchanted player's upkeep, that player creates a 1/1 white Soldier creature token.

Enchant creature
Enchanted creature can't attack or block.

When Settlement Establishment enters, draw a card, then choose a card name.
Whenever an opponent casts a spell with the chosen name, counter that spell, then that opponent creates a Plains token.

Flying
When Sha Long enters, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

When Sha'Iv Cagemage enters, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
Whenever an Aura you control enters, you may tap target creature.

Vigilance
Sha'Iv's Emissary gets +1/+1 as long as you control a blue or red permanent.

Create three 0/0 colorless Reflection creature tokens. Creature tokens you control get +2/+2 until end of turn.