* The National Dex is a feature in the Pokemon Diamond and Pearl games, not Diamond. The National Dex was introduced in Pokemon Platinum, which allowed access to all Pokemon from previous generations.
* Legendary Pokemon are generally rare and require specific methods to catch. This can include special events, specific locations, or completing certain tasks.
* Diamond does not have the features necessary to access most legendary Pokemon.
To find legendary Pokemon, you would need to play Pokemon Platinum or a later game in the series that includes the National Dex.
If you're looking to get legendary Pokemon on the Nintendo DS, you can try:
* Trading with other players: This is a common way to obtain rare Pokemon.
* Using the GTS (Global Trade System): You can offer Pokemon in exchange for legendary Pokemon.
* Playing events: Nintendo sometimes hosts events that allow players to catch specific legendary Pokemon.
Remember that acquiring legendary Pokemon through legitimate means can be a time-consuming process, so be patient and have fun!