He knew. I think he thought it was his only option. Lucifer and Michael were pitted against one another, and they were to have their battle on Earth. Regardless of who won, billions would die. But to exist on the earthly plane, angels need a vessel, and they need permission.
Dean said no in that timeline, but Sam said yes. They'd separated and gone their own way, so I'm not entirely sure of the circumstances of Sam's "yes". Lucifer is deception personified, so there's no telling what he told Sam in order to gain permission.
Sam does say yes in my timeline as well, but there was a plan in place. It almost didn't work, but in the end, Lucifer was placed back in his cage.
no subject
Dean said no in that timeline, but Sam said yes. They'd separated and gone their own way, so I'm not entirely sure of the circumstances of Sam's "yes". Lucifer is deception personified, so there's no telling what he told Sam in order to gain permission.
Sam does say yes in my timeline as well, but there was a plan in place. It almost didn't work, but in the end, Lucifer was placed back in his cage.
And yes, the devil-devil.