When you first beat the Elite Four, you will find that N has beaten the champion Alder, but after beating N in his castle, he will fly away on Reshiram and Alder will return to being the champion. But I personally (others agree) think that N is the champion. After all, he did beat Alder. But if you want fact and not opinion, Alder is the champion.
you dont battle alder n becomes the champion so you battle him then (if you beat him) you battle ghetsis.
The League champion in the games are N, the Team Plasma king. Also there is Alder the Pokemon black and white champion
Alder is only in pokemon black or white.
Alder
The Champion in Pokemon Black and White is only after you have defeated N and Ghetsis For the final time. Then the second time you battle the Elite Four/Pokemon League, You will battle Champion Alder. All his Pokemon are Lv 75.
Most of his Pokemon are bug type.
The champion which is alder has accelgor, escavlier, druddigon, vanilluxe, boufallant and volcarana
Alder the champion will give it to you on Twist Mountain.
trainer n he beats alder
you get him after the elite 4 and you have to find the light stone first which is the rock on display in necrene cities museum and that N guy get zekrom and you fight him instead of Alder the champion
Surf is given to you by Champion Alder at Twist Mountain