Recommended Levels: 46-57
There are a few good Poké’s in the Cave of Origin - other than your legendary, of course! Mawile and Sableye are the version-exclusive (OR and AS, respectively) main ones to look at.
Mawile is mostly used for its Mega Evolution, which is highly powerful due to its Huge Power ability. You should already have the Mawilite for Mawile’s Mega, too.
Sableye can now Mega Evolve as well, but it’s better known for trolling other Pokémon with its its Prankster ability (typically with Will-O-Wisp) and is notorious for popularizing the "SwagPlay" technique: that is, using Swagger, then Foul Play to capitalize on the target’s increased Attack.
Go along the path before you into the next area. There, round to the northeast side of the area and proceed downward.
Here, go southeast using the Dowsing Machine to get a Revive , then continue along down to the next area.
B2F and B3F
It’s a linear path here, too, just keep going as the earthquakes increase in magnitude.
Approach head northwest here and you’ll get into the Aqua/Magma Suit and will fit it out with the Blue/Red Orb. Soon thereafter, Kyogre/Groudon will arise. Archie/Maxie will call over on it, telling you to jump onto its back. What?
Despite that, you don Kyogre/Groudon much as you would a pimped-out horse and head into Hoenn’s Core. Even your PokéNav Plus begins to malfucntion from the electromagnetic and thermal radiation.
Save your game as soon as you can, then approach Kyogre/Groudon to the northeast. Once you get as close as you can, press the A button to begin the battle!
|Primal Groudon||Ground/Fire||Desolate Land||OR|
|Primal Kyogre||Water||Primordial Sea||AS|
If defeated, these Pokémon reappear here after the Elite Four, so don’t worry. In fact, hardcore trainers may wish to KO Groudon/Kyogre on purpose so they can later reset for great stats and/or nature at their own leisure.
While it is true that you can rebattle the legendary Pokémon, it will be after the Elite Four, hence why we recommended you save as having a legendary - especially one as powerful as a Primal - will put you at a huge advantage in the later game.
Still, despite this, the capture techniques remain the same. If it all comes down to it, you can always just use the Master Ball , though that’s better saved for something harder to catch. The ideal situations would be to either cause Paralyze or Sleep on the target.
Paralysis will be harder to induce on Primal Groudon, though, so Sleep can work well too. Point is, status and thereby inhibit to begin with. From there, simply hit it with low-power moves it resists, or, better yet, lots of False Swipe ; the latter cannot KO and may even proceed faster.
Whichever way of lowering HP is up to you; Poison/Burn also works, but comes with problems if you fail to capture. It’s really just the generic catching process: lower HP or status, do the other, throw Ultra Balls.