msem-instigator

Deathtouch
When Scion of Desolation enters, put target creature card with mana value 3 or less from a graveyard onto the battlefield under your control.
Whenever a Swamp you control enters, you may aetherize Scion of Desolation. (To aetherize, create a token that's a copy of it, then exile that token.)

When Scion of Fecundity enters, search your library for a creature card with mana value 2 or less, reveal that card, put it into your hand, then shuffle.
Revive—{1}{G}{W}, Discard a card. ({1}{G}{W}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Trample
When Scion of Flourishing enters, put a +1/+1 counter on each other creature you control. Those creatures gain trample until end of turn.
Whenever a Forest you control enters, you may aetherize Scion of Flourishing. (To aetherize, create a token that's a copy of it, then exile that token.)

When Scion of Pestilence enters, create a black enchantment token named Blight with “At the beginning of your upkeep, you lose 1 life.”

As Scion of Silence enters, choose a nonland card name.
Other permanents with the chosen name lose all abilities.

Vigilance
When Scion of Storms enters, create a 2/2 white Elemental creature token with flying.
Whenever a Plains you control enters, you may aetherize Scion of Storms. (To aetherize, create a token that's a copy of it, then exile that token.)

Flying
When Scion of Torrents enters, you may return target nonland permanent to its owner's hand.
Whenever an Island you control enters, you may aetherize Scion of Torrents. (To aetherize, create a token that's a copy of it, then exile that token.)

Scorch deals 3 damage to any target.

Scoured Barrens enters tapped.
When Scoured Barrens enters, you gain 1 life.
{T}: Add {W} or {B}.

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create two 1/1 white Human creature tokens.
II — Put a vigilance counter on target creature you control. It becomes a legendary God in addition to its other types.
III — Exile target creature an opponent controls that's a God or that has power 4 or greater.

Sculpted Observatory enters tapped.
{T}: Add {W} or {U}.
{1}, {T}: Add one mana of any color.

Whenever you sacrifice a permanent, you may pay {1}. If you do, you draw a card and you gain 1 life.

At the beginning of your upkeep, if six or more cards are in your graveyard, you may transform Scuttling Gnat.

Draw a card, then draw cards equal to the number of cards named Sea Cache in your graveyard.

Sea Of Skies Beyond enters tapped.
Whenever you cast a noncreature spell, put a creation counter on Sea Of Skies Beyond.
{T}, Remove ten creation counters from Sea Of Skies Beyond and sacrifice it: Shuffle your hand into your library, then draw five cards.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Sea's Allure enters, gain control of target creature for as long Sea's Allure remains on the battlefield.

Flash
When Seabreen Nullmage enters, counter target activated or triggered ability. (A triggered ability uses the words “when,” “whenever,” or “at”. Mana abilities can't be targeted.)

Concord — {1}{G}: Until end of turn, Seadrake Rider gets +2/+3 and must be blocked if able. Activate only during your turn, only once each turn, and only if there are four or more card types among permanents you control.

Flash
{U}, Sacrifice Seal of Approval: Counter target spell unless its controller pays {2}.

Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.
Scry 1.

When Sealed Riftway enters, exile up to one target card from a graveyard.
{2}, {T}, Sacrifice Sealed Riftway: Exile target player's graveyard. Draw a card.

Sear Flesh deals 3 damage to target creature or planeswalker. If you've cast another spell this turn, it deals 5 damage instead.

This spell costs {2} less to cast if you activated an ability that's not a mana ability this turn.
Searing Grace deals 3 damage to any target.

Target permanent you control deals 2 damage to any target.
Inscribe {2}{R}{R} ({2}{R}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)