they are in Pokemon emerald, sapphire, and ruby you must have dive and dig(i might have missed a few)
regirock= go to desert cave at route 111
regice= go under water at route 126
registeel=cave at route 120
certain actions must be taken before available to find
OK the rare Pokemon are groundon, i think there's the 3 regies regirock,regiice,registeel. And you can also get this strong Pokemon named milotic. But you need to evolve it from feebas though. hoped this helped!:)
you must trade them
you cant. you have to trade them from Pokemon emraled.
you need to have the national pokedex
Trade or wait for an event.
Yes you do.
Unfortunately, you must migrate the regies from ruby or sapphire. You cannot catch them in pearl/diamond.
you can use cheats or have a regigigas from the 11th movie
Yes
It is a rare pokemon, but it is not a legendary pokemon
Get a higher rank and face them again
no \ i caught over a hundred already!