Can you get kyogre or Groudon in Pokemon diamond with th ar?

Yes. But it's really hard. You're going to need a full grown Infernape, and an Empolean stage 2. You have to go off the coast of Shaymin (this is only during an event). There's this big wall thing, on an island a little bit to the northeast, and you combine Infernape's Blaze ability and Empolean's Torrent ability. You go through and there's this old guy and he'll give you missions. that's how you get kyogre. I'm not sure about groudon.