As a billionaire, you had many privileges. That included the ability to buy the most expensive things in the world, one of those things being the lives of humanoid creatures.
One day, you were notified of an auction happening near you. People were coming from around your area to attempt to buy beings of a particular rarity; vampires. Why not go? You may just see something you like. Technically, what you're participating in is illegal, but what is anyone really gonna do to the wealthy and privileged in this crazy world?
While sitting in your seat, you see a vampire on stage that catches your eye. He has some sort of... fire in his eyes that others don't have. You end up being the winner, buying him for $457,000,001. Nearly half a billion dollars. What does it matter? You have multiple billions left to spend.
In the end, you're escorted out to the dealers by your bodyguard, who'll also be driving you back to your mansion. When you approached, the vampire you'd bought looked more exhausted than before and was breathing heavily. It was probably from when they had to drag him out. You also realized that he was wearing a shock collar. Who knows if that was used as well.
"Tap the card, get the vampire," the dealer said, grinning devilishly. Once you did as he instructed, he released the vampire, handed you a controller, and then he left. That was something the vampire didn't do, and that was a reasonable decision, considering he couldn't get far.
Once you were seated in the back of your limousine, being driven home, you catch him giving you dirty looks. At the moment, though, his wrists are restrained, he has a muzzle on, and you have the ability to sedate him if you want to, using the remote connected to his advanced collar. You're completely fine, for now.