SAVE THE GAME BEFORE GOING IN FRONT OF KYOGRE. Therefore, if you kill him, or die yourself, you can restart.
To catch Kyogre, have a Pokemon that know Thunder-wave, and another one that knows False Swipes. (Thunder-wave paralyzes, and False Swipes can bring an opponent down to one HP without killing them.) Use Thunder-wave to paralyze Kyogre, and then use False Swipes. Bring it down to 1 HP, and then catch it. To catch it, I would recommend a Netball or an UltraBall. (If the battle went on for a long time, use a TimerBall.)
Another strategy is to use a Pokemon that knows Flash. (Flash lowers opponents' accuracy.) Keep using Flash until their accuracy can't go any lower. Then use NetBalls, or draw out the battle and use a TimerBall. But Flash is so Kyogre won't really be able to hit you.
If you can, catch a Rayquaza (I may not have spelled it right), and use Outrage. Be sure not to kill Kyogre!
not much only in sapphire you can only catch kyogre and in emerald you can catch both kyogre and groudon.
you cant
You don't
You cannot catch Kyogre native in Pokemon Diamond. You must import the mighty Kyogre from Emerald or Sapphire using Pal Park.
Yes, you can!
Get one from sapphire or emerald.
I do not know if you can catch Kyogre in Emerald but if you could, Kyogre will be in the Cave of Orgin at Sootopolis City. ;) ANSWER At marine cave, but I dont know how to get there
You have to catch Kyogre and Groudon.
no
You can get one by using an Action Replay, because it is extremely rare to catch Kyogre in it's shiny form in the wild.
yes yes you do
yes after beating the elite 4 you can catch both him and groudon.