The things that the two of them can ask for are endless if their plan succeeds. They will not be restricted to the usual things that everyone will ask the realm lord for if they win a favor from him. The usual favor has to do with becoming a world god. They don't need his help for that. They might be participating in the same era of conquest as others, but they are not like others. They are dragons.
A single realm tree can make billions of Immortal origin gods while a single realm heart can create only a single world god. That means that not every origin god can become world gods with a realm heart no matter how talented or special they are. Their chances are reduced even further by the fact that some world gods are actively destroying the already insufficient realm trees.
