As a child, Klaus has an unorthodox birthday wish
"Tomorrow is my birthday Father!" Klaus said with glee.
"I know that, I was just kidding. Seriously, Klaus, what do you want for your birthday?"
"I want a pony, and I want a dog, and I want... and I want...," Klaus's list went on. Finally, the list came to an end, "I want you, mother, and me to live forever. Then I will never have to grow up!"
It was only this last request that truly bothered Gustav. The others were things that would only cost money and could be found anywhere. The last, he could only receive from a vampire and it would cost Klaus his soul. Klaus did not know much about vampires yet, Gustav wanted Klaus to have some semblance of a childhood before he was indoctrinated with the Helsing family tradition of vampire hunting. But he could not help wondering what if Dracula just heard Klaus's wish? "No, he would not have heard that," he thought.
Little did Gustav know, Klaus's pleads for immortality reached Dracula's ears. Dracula was there and he was listening. "Just wait, my dear little Klaus. I will come for you when you are older and I will be able to give you everything your heart desires."