The whole idea of Vaas being alive was stupid to me and I was very close-minded about the topic. But then, when I was thinking about it, I got lost in my deep thoughts and started thinking about how he opened his eyes at the end of the scene. I thought about what he said, how it could have been a dream, thinking through what happened in the dream, how you wake up at the temple, not Vaas's island, just all that. My theory is, that the reason Vaas seemed dead is because the game developers wanted you to think that. He could be alive, he could be dead. The thing is though, Vaas always asks the player, "Have I ever told you the definition of insanity?", you think, "yes, about 1,000 times already!". It's doing the same thing over and over and over again, expecting things to change, right? Exactly. He always tries to kill Jason and Jason always tries to kill Vaas. So Vaas is alive, they're the same people. Vaas' body is dead, but his soul was in Jason. So, that's why I think Vaas is still alive.