msem-instigator

{4}{R}: Blind Tunneler gets +3/+0 until end of turn.

Enchant creature
Enchanted creature gets +1/+1 and has hexproof.

When Blisterbug dies, put two +1/+1 counters on target creature you control.

{T}: Add {C}.
Dominance — {1}, {T}: Blistering Boneyard deals 1 damage to each opponent. Activate only if you control the creature with the greatest power or tied for the greatest power.

Advance {1}{R} (Cast this for {1}{R} to advance it as it enters. {1}{R}: Advance this as a sorcery.)
Whenever Blitz Breaker advances, its power becomes equal to the amount of noncombat damage that's been dealt to your opponents this turn. (This effect lasts indefinitely.)

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.

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

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

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.

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.)

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.

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

Deathtouch
{T}, Sacrifice another creature: Add two mana of any one color.

Sacrifice another creature: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Bloodcrazed Acolyte enters with a +1/+1 counter on it for each player who lost life this turn.

Whenever Bloodcrazed Instigator attacks, target Rebel creature you control gains first strike until end of turn.

Bloodfell Caves enters tapped.
When Bloodfell Caves enters, you gain 1 life.
{T}: Add {B} or {R}.

Flying, menace, haste
When Bloodfiend Ravager enters, it deals 2 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Flying, haste
{1}{R}{R}: Return Bloodfire Phoenix from your graveyard to the battlefield. Activate only if an opponent lost 3 or more life this turn.

Equipped creature gets +1/+1 and has lifelink.
Whenever equipped creature dies, if it wasn't a token, you may pay {3}. If you do, create a token that's a copy of that creature and attach Bloodguard's Hand to it.
Equip {3}

Whenever you discard a card or an artifact is put into your graveyard from the battlefield, put a +1/+1 counter on Bloodhollow Bruiser.
Cycling {2} ({2}, Discard this card: Draw a card.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodied Twinblade dies, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

{T}: Choose a color of a card in your graveyard. Add one mana of that color.

{G}, {T}: Put a +1/+1 counter on Bloodleaf Tracker for each creature that entered this turn.