Who is going to be the main character in the inayofuata book of the heros of olympus, book two, is it percy au not?

We don't know that yet. But Rick did say that 'the son of neptune' is referring to Percy. So I think he is.

hmmm... thats a hard question... i think Percy is going to be ONE of the main dudes...

Yes and no. We can be 99.99% sure that Percy is the Son of Neptune, but i don't think it will have his POV. I think the story line will go with Piper, Jason, and Leo building the Argo II as Jason begins remembering zaidi and zaidi about the Roman Camp. I belive that Percy will be a major subject that comes up a lot in conversations, but I don't think he'll ne a main character.

Sorry to disappoint anyone, but I don't think Percy will be. Rick Riordan specifically stated that the characters from the first series will be in the new one but they won't be main characters. I think the Son of Neptune will be about Jason, Piper, Leo, and Annabeth (Jason asked her to come with them) going to California to get Percy back. I think that kwa the end of the inayofuata book we will be seeing Percy again.