Anyone who has been following the National Cipher Challenge since it started will realise that either Harry is very, very old (and surprisingly sprightly for his age) or he has a time machine. Possibly both. He also has a PhD in Mathematics which makes him feel rather a lot like the Doctor, a comparison he does nothing to discourage. The Elves who run the forum however, violently reject the idea that they are in any sense "Companions", and anyone who has seen an Elf fighting their way through a horde of Orcs will know that it is never wise to anger one. If you want to meet Harry and the Elves you could try coming to a University of Southampton Open Day or offer holder day and identifying yourself as a Cipher Challenge fan!