According to simulations run on different futures of Ignis and humanity, Revolver says that Lightning's is the only one that leads to mutual destruction.
Then I summon Estrangement 
Dragon from my hand!
Danach beschwöre ich Estrangement Dragon
von meiner Hand!
¡E invoco a Strangement Dragon
desde mi mano!
Então eu invoco o Estrangement
Dragon da minha mão!