8. Hulk (The End)
In one possible future for the Marvel Universe, the Hulk exists as the last living person on Earth. There aren't many animals, and absolutely no people remaining on the planet, and the Hulk finds himself where he wanted to be for so long: he was finally alone.
That's not entirely accurate, seeing as Bruce Banner was still there. Granted, he was a suppressed psyche at this point since the Hulk remained in control of their shared body. Hulk shared the world with its dominant lifeform, which was a type of mutated cockroach. Roaches swarmed across the world, eating whatever they found.
This included the Hulk, and despite all his strength and durability, the roaches were able to eat large portions of his body. When this happened, he healed, as his strength and other powers were essentially maxed out.
Eventually, Bruce Banner dies while the Hulk is still in control of their body. He sensed the loss and realized that a change back into Banner would kill him. This gave him some comfort momentarily, but then he realized that he truly was alone with the thought, "Hulk...strongest one there is. Hulk...only one there is...Hulk feels...cold."