You don't. All legendarys in all Pokemon games are like this exept for latias and latios, you get to fight them once, that's it. No second chances. If you killed regirock and saved, he gone forever. What I do is i save right before i fight any legendary and if i kill it then i turn it off and fight it again
Regirock, Regice, and Registeel.
there are three that you can CATCH in pokemon emerald its Groudon, Kyogre, and rayquaza regice registeal regirock litos lotias
Only in Ruby, Sapphire, and Emerald.
You need a Gameshark code, or, if you have a friend that has beaten Pokemon emerald already, you just trade the Pokemon over to them and let them do the cloning glitch. So what i am basicly saying is that you cant clone early in Pokemon emerald.
The easiest way would be to RNG abuse, but this is in the wrong category.
to get regirock in Pokemon platinum, you have to upload it from ruby, Sapphire, or emerald.
RegiRock
You can only get Regirock by transferring a Regirock from Pokemon Ruby, Saphire, or Emerald to the Pal Park I believe.
you cant. you have to migrate them from Pokemon emerald
In Diamond you can't catch Regirock, you have to migrate it from Pokemon Ruby, Sapphire, or Emerald.
No, you need to trade it from Emerald.
Regirock, Regice, and Registeel.
you need the national. dex and need to have beaten the elite four. then you migrate regice, regirock and registeel from Pokemon emerald, ruby or sapphire. have them all in your party and go to the temple in snowpoint city.
no you can, you most catch it in Pokemon emerald
you can gain regirock by getting the national pokedex the going to pal park then transferring it from Pokemon ruby or emerald then cath it
there are three that you can CATCH in pokemon emerald its Groudon, Kyogre, and rayquaza regice registeal regirock litos lotias
u have to migrate them from ruby Sapphire emerald