Nexon has this new thing where they will release specific characters at a specific time for a certain amount of time.. Hayato was available for creation a couple weeks ago prior to hyper evolution update.
"Sometimes it actually is greener on the other side."
When will it be available then? Kinda sucks, seriously.
That is not known, but we can speculate that during 8th anniversary, which starts in May, is the earliest all classes will be available again. However, don't expect them until June at the earliest if they can't be made in May.