Sorry, the web site is in french because I'm French. ^^' You can go at this place when you have viewed all the pokemon of Unys. When it's done, you go to talk to the pokemon professor. You get a special pass and you can go to a secret area name "Réserve naturelle" (in french) from the airport of "Parsemille". At the center of this place, a shiny Haxorus waiting for you.
Fortunately, I've written all the things you have to do in order to obtain this shiny haxorus. I'm sure that this kind of help/solution site exists also in english.
I have one shiny in Pokemon Black 2.
Sorry, the web site is in french because I'm French. ^^'
You can go at this place when you have viewed all the pokemon of Unys. When it's done, you go to talk to the pokemon professor. You get a special pass and you can go to a secret area name "Réserve naturelle" (in french) from the airport of "Parsemille". At the center of this place, a shiny Haxorus waiting for you.
I'm sure that this kind of help/solution site exists also in english.