Cast Scholar of the Lost Trove by paying {5}{U}{U}.
Scholar of the Lost Trove enters the battlefield, triggering itself and Impact Tremors.
Resolve the Scholar of the Lost Trove trigger, casting Worldfire from your graveyard without paying its mana cost.
Resolve Worldfire, exiling all permanents, all cards in all hands and graveyards, setting each player's life total to one, and exiling Worldfire.
Resolve the Impact Tremors trigger from step 2, dealing 1 damage to each opponent.
Each opponent loses the game due to having zero life.

Each opponent loses the game

Exile all cards in all hands and graveyards

Exile all permanents

Near-infinite lifeloss for all players

Scholar of the Lost Trove

Worldfire

Impact Tremors

Activate Helvault by paying {1} and tapping it, exiling Scholar of the Lost Trove.
Activate Krark-Clan Ironworks by sacrificing Helvault, adding {C}{C}.
Helvault leaves the battlefield, returning Scholar of the Lost Trove from exile to the battlefield.
Scholar of the Lost Trove enters the battlefield, casting Helvault from your graveyard without paying its mana cost.
Repeat.

Combos with "Scholar of the Lost Trove"