Sway of the Stars by paying ({8} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing each player to shuffle their hand, graveyard and all permanents they own into their library, then causing each player to draw seven cards and set their life total to 7.
Nadier's Nightblade triggers for each token you control that leaves the battlefield, causing each opponent to lose at least 7 life and you to gain at least 7 life.
Each opponent loses the game due to having 0 life.
Results
Each opponent loses the game.
Near-infinite lifeloss for all players.
Shuffle all hands, graveyards and permanents on the battlefield into their owner's library.