msem-instigator

Whenever Blood Constrictor becomes blocked by a creature, you gain life equal to that creature's toughness.

At the beginning of each end step, if an opponent lost life this turn, you may put a +1/+1 counter on target creature.
Sacrifice a creature, Sacrifice Blood Cult Covenant: Blood Cult Covenant deals damage equal to the sacrificed creature's power to any target.

Menace (This creature can't be blocked except by two or more creatures.)
Blood Fiend can't block.
{1}{B}, Pay 3 life: Return Blood Fiend from your graveyard to the battlefield. It gains haste.

Target creature gets +3/-3 until end of turn.
Kindle 3—{B}{R}, Pay 3 life. ({B}{R}, Pay 3 life, Exile this card from your graveyard: Create three 1/1 colorless Elemental creature tokens. Kindle only as a sorcery.)

Nonbasic lands have “Whenever this land becomes tapped, you lose 1 life unless you sacrifice this land.”

Whenever equipped creature attacks, choose target creature defending player controls. Destroy that creature at end of combat.
Equip {4}

When Blood Jade Prophet enters, reveal the top three cards of your library. For each card revealed this way, you may pay 3 life. If you do, put that card into your hand. Otherwise, put it into your graveyard.

As an additional cost to cast this spell, sacrifice any number of creatures.
Target player loses 2 life for each creature sacrificed to cast Blood Lashing.

Draw a card for each creature that died this turn.

Exile up to three target cards from a single graveyard. You gain 3 life.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Blood Servant enters, if it engorged a creature card, you draw a card and you lose 2 life.

{1}{B}, Sacrifice another creature, Discard two cards: Search your library for a card, put that card into your hand, then shuffle.

At the beginning of your upkeep, each player sacrifices a nonbasic land.

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Target creature gets -4/-4 until end of turn. If that creature would die this turn, exile it instead.
Cycling {2} ({2}, Discard this card: Draw a card.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
Each opponent discards a card and loses 2 life.
Exile target card from a graveyard. If a creature card was exiled this way, you gain 2 life.
At the beginning of the next end step, you gain 3 life if an opponent lost life this turn and each opponent loses 3 life if you've gained life this turn.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Target creature you control gets +1/+0 until end of turn.
[Lore III] Target creature you control gets +2/+0 until end of turn.

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Blood-Tithe Harpy enters, target player loses 1 life and you gain 1 life.

Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
As long as Bloodbelly Glutton is embattled, it has first strike, menace, and haste. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Whenever you sacrifice a creature, you may pay {B}{G}. If you do, put a +1/+1 counter on Bloodblade Mercenary and draw a card.

Haste
Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Bloodboil Harlequin desecrates a permanent, up to two target creatures can't block this turn.

Lifelink
{1}{B}, Sacrifice Bloodbond Ritualist: Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

{B}, Discard a card: Bloodbraid Ritualist gains indestructible until end of turn. Tap it.
At the beginning of your upkeep, you may have Bloodbraid Ritualist consume. If you do, draw a card. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

When Bloodbriar Acolyte dies, draw a card. Each opponent loses 1 life.

Trample
{T}, Sacrifice another creature: You gain 3 life.
Whenever another creature you control dies, put a +1/+1 counter on Bloodbriar Archdruid.