"So we were getting played all along?!" Dean bellowed "EVERYTHING that happened over the last three years was so we'd end up being used to free you from Purgatory?!"
"Bingo." Zachariah replied with a cocky tone. "But if it makes you feel any better, Cas really was your friend. Crowly just knew the right buttons to push to make Cas do exactly what we wanted. We played him the same way we played your family."
"Well there's a problem with your plan Zach." Dean said with an obvious air of defiance.
"What's that?" Zachariah asked with a laugh.
"Sam's about to kill you and when he does he and I are gonna get past these last few years. You're not gonna win Zach."
"Oh you're wrong Dean. If I die you die with me and in turn Sam will die cause he can't stand the thought of letting you go alone again. He can't stand the thought of you coming back disapointed in him again. He'd rather burn in Hell than feel the pain of your rejection again. I die, you die, he dies, I win. It's as simple as that."