Near the end he comes back with his Reshiram/Zekrom wich merges with Ghethsis' Kyurem making Black/White Kyurem
Yep.
Source
In Pokémon Black and White 2, N returns to save Kyurem from Ghetsis riding ZekromB2/ReshiramW2. When his legendary dragon is absorbed by Kyurem to transform to Black KyuremB2/White KyuremW2, he pleads the player to stop Ghetsis and get it back. On Route 23 on the way to Victory Road, he will give the player HM05 (Waterfall) after the player has entered the Hall of Fame, N's Zoroark will appear on Victory Road and lead the player to the ruins of N's Castle, which N and the player walk around. In the throne room, N asks the player to battle him and his ZekromB2/ReshiramW2. When the player defeats him, N reverts his dragon to its dormant state—the Dark StoneB2/Light StoneW2—and gives it to the player to summon it at Dragonspiral Tower to catch. After catching ZekromB2/ReshiramW2 and Kyurem, N appears in Nimbasa City near the Rondez-View Ferris Wheel on Fridays. After riding with him, he returns to the ruins of his castle, which now form Victory Road for a rematch with different Pokémon depending on the season