This deck wins through two compact instant-speed combos: Demonic Consultation naming Thassa's Oracle exiles your library and wins immediately when Oracle enters, while Gravecrawler plus Pitiless Plunderer plus Ashnod's Altar generates infinite colorless mana and death triggers. Toxrill, the Corrosive serves as a secondary lock—each end step it puts slime counters on opposing creatures, and with Maha, Its Feathers Night reducing their base toughness to 1, they die as a state-based action, generating Slug tokens you can sacrifice to draw cards.
Demonic Consultation combo: Cast Demonic Consultation for one black mana, name Thassa's Oracle (which you don't have in your library), exile your entire deck, then cast Thassa's Oracle for two blue mana. When Oracle enters, you win because your library is empty and Oracle's devotion-to-blue check (counting the {U} symbols in your permanents' mana costs) exceeds zero. This line is tutored by Mystical Tutor and Entomb, plus 3 more tutors, making it highly consistent. Pitiless Plunderer triggers, creating a Treasure token. Tap and sacrifice the Treasure for one black mana. Cast Gravecrawler from your graveyard for one black mana. Repeat infinitely, generating infinite mana and infinite death triggers to drain the table with Blood Artist, Necroskitter, or Braids, Arisen Nightmare. Buried Alive tutors all three pieces into your graveyard in one spell. Toxrill lock: Toxrill enters as a 7/7 and begins putting slime counters on each opposing creature at end step. You generate Slug tokens from each death, which you sacrifice to Toxrill's activated ability ({U}{B}, sacrifice a Slug) to draw cards, turning the lock into card advantage. This line requires both pieces in play but locks the table if neither is removed. Setup and acceleration: Sol Ring and Arcane Signet, plus 2 more ramp pieces provide early mana. Mind Stone doubles as ramp and card draw. Dark Ritual accelerates into turn-2 plays. Mystical Tutor, Vampiric Tutor, and Profane Tutor find combo pieces or tutors themselves. Ad Nauseam draws your deck when you have low-mana-value permanents, fueling spell chains. Muddle the Mixture counters interaction while transmuting into Demonic Consultation or other two-mana spells.