You do realize that either work, right? N works with Zekrom because he hopes for his ideal world where Pokemon can live in peace without humans, and Hilda/Hilbert show him the truth that there are humans that treat Pokemon well, and N changes his ideals to try to tighten bonds between humans and Pokemon. With Reshiram, it's N's desire to find the truth, and his warped perception that humans are innately harmful to Pokemon becomes his truth, but Hilda/Hilbert's idealistic mindset to forming a better world and having humans and Pokemon live together are what eventually prove him wrong, and N realizes the real truth.
