First you have to complete all Gym Leaders & get all of the badges. Then you head to the Pokemon League.
free roam
after you beat the Pokemon league
If you havent beaten the Pokemon league then level them up a bit then defeat the Pokemon league
Accelgor, Bouffalant, Escavalier, Druddigon, Vanilluxe and Volcarona and that applies for both Pokemon Black and White.
There is a secret path in the Pokemon League and you have to follow it to get to him.
At The end of victory same Place as white
Dark, Psychic Fighting and Ghost type
No, you dont see him again.
yes you can he should be at black city or the pokemon league or white forest
If you are playing the first black and white: Dark,Fight,Psychic and Ghost pokemon!! In black and White 2 i don't know
The League champion in the games are N, the Team Plasma king. Also there is Alder the Pokemon black and white champion
For now, he didnt, but he will at the Unova League!