Legendary Pokemon from previous generations have been found in Black and White 2. I’ve kept the details in the full story to prevent spoilers.

Latios, Latias, Regigigas, and Uxie have all been found in Black and White 2. Not much is known yet about their appearances. They may be part of the game’s story and you might be able to catch them. The screenshot below of Uxie shows Professor Juniper by the player.

Uxie and Professor Juniper

Regigigas

Latios

 Latias