in Lala land
The legendaries on Pokemon black are Tornadus, Kyreum, Reshiram, Cobalion, Terrakion, and Virizion. I can help you find them, too!
In Pokemon Black you can actually get quite a bit of legendaries. You can Get Reshiram, Kyuram, Giratina, and Arceus. Also Kyogre and Groudon.
You cannot obtain Thunderous in Pokemon Black, only in Pokemon White, since it is game-specific, like other legendaries. As for Landorus, you can find it in the Abundant Shrine.
5 legionaries
none
I put a link to guide on all the legendary pokemon in Pokemon Black in the related links.
All except for Garitinia and all from Pokemon black and white.
They are similar but they have different legendaries. *Source- Played Pokemon when I was little.
You can beat cynthia beat the Pokemon league again find the legendaries complete the poked ex and your basically done with the game
You Have To Beat All Of The Gyms, Elite Fours And the Champions. But Its Complicated To Find Legendaries.
No. Pokemon Black and White are the only current games with no legendaries not belonging to their region. It can be traded from other games, though.
No, you can't find all the legendaries in Diamond. There isn't a Pokemon game with all the legendaries in it. You can capture 8 legendaries in Diamond, f you want all the legendaries, you'll need to visit events, trade or migrate them.