Regice, Registeel, Regirock, Latios, Rayquaza.
...sigh. groudon is a legendary, it does NOT evolve
Groudon and Rayquaza
Groudon the big red one
groudon but in a updated version.
You can only get groudon if you migrated it through the pal park from Ruby or Emerald.
RayquazaRare or Legendary? Legendary, the same in Ruby and Sapphire. Groudon, Kyogre, Rayquaza, Latios/Latias, the Regis. Not very many, rare pokemon,besides what you can get after the national dex, like sudowoodo, or smeargle.
Latios, Groudon, Rayquaza, Regirock, Regice, Registeel.
Groudon, Regirock, Registeel, Regice, Rayquaza, Latios.
Regirock, Regice, Registeel, Latios, Groudon, Rayquaza.
The Legendary Pokemon in Ruby are Kyogre, Groudon, Rayquaza, Deoxys, Jirachi, Latios, Latias, Regice, Regirock, and Registeel.
In Pokemon Ruby and Sapphire there is no battle between Kyogre and Groudon. That is only in Emerald version. Instead the legendary pokemon (in your case Groudon) is inside the cave of origin in Sootopolis City.
you can catch groudon in ruby in cave of origin then beat the elite four to catch rayquaza on sky pillar