There aren't a lot of people that actually realise it means Demon Raichu, so I congratulate you for know a miniscule bit of a langauage.
But yes, there is. Especially seeing as Raichu is not my favourite Pokemon. Espeon long ago stole that crown. Basically, I was playing my Diamond version on the fourteenth of December, which was (amazingly enough) the same day I joined this forum. While I was playing, I gave my Pikachu a Thunder (or is it Lightning? I can remember) Stone and it evolved into Raichu. I had name the Pokemon Oni when it hatched into a Pichu, and I realised Oni Raichu had a nice ring to it. I registered under the name of Noah Fowl EX after I nocticed there was a Super Moderator going around with the username, Oni Pichu (who is now using the username Careful With That Axe, Pichu) and I asked him if I could have permission to use the username Oni Raichu. He said yes, myself and Sammi had an argument in which she told me I could make a new account if I really badly wanted a username due to the fact that the administrators won't change a username for four months.
So, yeah, it was made from my desire to breed the perfect Pichu.