no you have to get regirock regiice and registeel
Dialga, Azelf, Uxie, Mesprit, Regigigas, Heatran Cresselia, Giratina, and Rotom. You can get others from Pokemon events and the Global Trade Station.
The Legendary Pokémon that you can catch in Pokémon Diamond are Dialga, Uxie, Mesprit, Azelf, Heatran, Regigigas, Giratina and Cresselia. Regigigas is only available for capture if you have Regirock, Regice and Registeel in your party.
Mesprit roams Sinnoh.
Uxie; Mesprit; Azelf; Dialga; Palkia; Heatran; Regigigas; Giratina; Cresselia; Phione; Manaphy; Darkrai; Shaymin; Arceus
In platinum you can catch Giritina, Palkia , Dialga, Heatran, Moltres, Arcticuno, Zapdos, Cressilia, Uxie, Mesprit, Azelf, and Regigigas. With the action replay you can also get Shaymin, Darkrai, and Arceus.
Not sure how either because i go inside all the caves and registeel or the others are not there and i think you need regigigas to catch the others or its the other way.
yes you can and you can catch them after you catch dialga/palkia/giratina
No. Mesprit, Uxie and Azelf can be caught normally, they're just extremely hard (especially Mesprit).
Catch better Pokemon
you can not get regigigas! but you can catch regice, regirock, registel.
no
you can catch mesprit after the championship on the wild >