How to get Lengendary pokes such as Diagla, Giratini or other legandary pokes?

In games corner u can see a couple of legendary but i dont know where to get dialga

most legendaries can be brought from the game corner with coins.

Regice is the only legend you can find on the map is really common, so it not rare.

the rest of the legendaries can be obtain when Da Man decide to put them as the promos.

Also Lugia, Celebi, Ho-oh: can be contain from the Battle Towers, but they are really hard to defeats now since Da Man changes the moves on them.

Dialga- was the promos for Father Day this year.