Why do you have to have the event Celebi to get Zorua?

Question

I was wondering why you e to have the event Celebi to get Zorua in Pokemon B and W?

Answer 1

I think the Celebi had something to do with the new Pokemon movie, Zoroark - Master of Illusions, just like the shiny Suicune, Entei, and Raikou giveaway event did (trading them to B or W connects to capturing Zoroark).

Comments

Celebi saved Mi-Ma, Zorua's foster parent. The shiny Entei, Raikou, and Suicune helped stop Kodai from capturing Celebi and the Time Ripple.