Kozilek, Butcher of Truth gives ramp decks a large colorless threat that refills the hand when cast. The cast trigger draws four cards, helping replace the resources spent reaching ten mana. If Kozilek attacks, annihilator four forces the defending player to sacrifice four permanents before blockers, creating pressure on their entire board rather than only their life total.
Eldrazi Temple and other colorless acceleration help reach the casting cost, while a developed land-ramp engine can support Kozilek in green decks. Haste sources are valuable because the first attack can remove important resources before an opponent gets another main phase. The creature has no built-in trample, so a small blocker can still absorb its combat damage after annihilator resolves.
Casting matters for the draw trigger. Putting Kozilek directly onto the battlefield through another effect skips that trigger, even though the creature retains its attack ability. If the spell is countered, the cast trigger can still resolve independently, which gives a normal cast some value even when the large body does not survive the stack.
When Kozilek enters a graveyard from anywhere, its owner shuffles that graveyard into the library through a triggered ability. That can protect resources from ordinary milling, but it also makes conventional graveyard plans awkward and can be answered before the trigger resolves. Choose Kozilek when your deck can cast expensive threats and wants a combination of card refill, board pressure, and library recycling.
