Chthonian Nightmare and Lion's Eye Diamond on the battlefield.
You have at least ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) .
You control at least one additional creature.
Steps
Activate Lion's Eye Diamond by tapping and sacrificing it and discarding your hand, adding ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) .
Activate Chthonian Nightmare by paying ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) , sacrificing another creature you control, and returning Chthonian Nightmare from the battlefield to your hand, returning Emry from your graveyard to the battlefield.
When Emry enters the battlefield, it and Inalla trigger.
Resolve the Emry trigger, causing you to mill four cards.
Resolve the Inalla trigger, causing you to pay ({1} magic symbol) to create a token copy of Emry with haste.
Put the nontoken Emry into your graveyard due to the legend rule.
When the Emry token enters the battlefield, it triggers, causing you to mill four cards.
Activate the Emry token by tapping it, allowing you to cast Lion's Eye Diamond from your graveyard this turn.
Cast Lion's Eye Diamond from your graveyard by paying ({0} magic symbol) .
Cast Chthonian Nightmare from your hand by paying ({1} magic symbol) ({B} magic symbol) .
Activate Lion's Eye Diamond by tapping and sacrificing it and discarding your hand, adding ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) .
Activate Chthonian Nightmare by paying ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) , sacrificing the Emry token and returning Chthonian Nightmare from the battlefield to your hand, returning Emry from your graveyard to the battlefield.