msem-instigator

Discard your hand, then draw two cards.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
When Blind Sharpshooter becomes renowned, it deals 2 damage to target creature defending player controls.

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

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.)

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.

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.

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.

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.

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.)

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)

({T}: Add {R}.)
Bloodriver enters tapped.
When Bloodriver enters, target creature you control gains haste until end of turn.

Discard a card: Bloodshot Berserker gets +1/-1 until end of turn. Any player may activate this ability.

When Bloodsoaked Blades enters, creatures you control get +2/+0 until end of turn.
Equipped creature gets +1/+1.
Equip {1}

Creatures you control that have been dealt damage this turn get +2/+0.
When Bloodspawn enters, it deals 1 damage to target creature you control.

Align X (Choose modes with total ★ less than or equal to X. You may choose modes multiple times.)
• ★ — Bloodstained Calamity deals 1 damage to each creature, player, and planeswalker.
• ★★ — Return target instant or sorcery card from your graveyard to your hand. Exile Bloodstained Calamity.
• ★★★★★ — Bloodstained Calamity deals 10 damage to any target.

{T}: Another target Warrior you control gets +1/+0 and gains haste until end of turn.

Whenever Bloodthirsty Insurgent attacks, it gets +2/+0 until end of turn.

Target creature gets +1/+0 and gains first strike until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)