You didn't post the details of what exactly is involved with a "vampire initiation fee": is this simply the purchase of an physical object? Or the purchase of a service, such as the placing of a spell or the providing of the service of alleged protection from vampires? Or is this some form of a real "Advance-fee scam" where money and banking credentials or personal information is involved? (See link below).
But in the big picture, one person's scam is another person's persuasive business sales pitch for an unusual item or service. Simply being able to pay for such an item or service doesn't make the sale - or the contract to sell it - illegal everywhere.
It may be the case that selling an "vampire initiation fee" does not happen to be illegal in Nigeria. Illegal in the US, possibly yes. illegal there? Maybe not. Contract laws differ; in the US, contracting for something that is illegal voids the contract. In Nigeria, maybe not.
Though the "vampire initiation fee" doesn't sound to me like a classic Advance-fee scam (Wikipedia), Google search on 419 scams and the results will tell you that it will be nearly impossible to get a prosecutor in that country to deal with anything like that, even if it is a real scam that promises lots of money for an upfront fee. Prosecutors have much better things to do. And you might have to go to Nigeria to make your case; see other answers that more fully outline the laws and legal aspects.
Good luck. And it's better to spend your money on some garlic and a mirror.
7/03/18 Update re: the email transcript linked in question
That's not a scam; the person is simply trying to sell you on the initiation fee. There is no crime.
There is no promise of more money for a small fee (and bank
credentials or personal information) like a typical 419 advance fee
You're not producing useful evidence for a prosecutor by engaging in
the email and mostly agreeing to pay him.
It's not illegal for you to send money by Western Union for the
Even if you did send money, you're not being defrauded
because you already know the vampire initiation is fake, and as a
result you couldn't logically prove to a prosecutor or court that you
He's not guilty of fraud as no money has changed hands for a
Emailing with him might make you feel good by wasting his time, but