ShadowStar91: Yes, the woman with Orochimaru is indeed Gurren. I don't mind telling you that as it won't ruin the plot. I plan on setting her up as the antagonist for Anko and Haku in this arc while Naruto and Akane fight their own enemies.
The Distorted Shadow: Well, you know what they say: "If you're going to give Frodo Baggins a lightsaber, then you need to give Sauron the Deathstar." This is more or less running along the same lines. Naruto and Akane are completely overpowered. There is no one in canon aside from maybe Uchiha Madara, or maybe that Kaguya Otsusuki chick who Kishomoto seems to have made into the new Mary Sue villain, that can stand up to them. Thus, I am giving them more powerful opponents. Eventually, Naruto and Akane will be facing enemies that far outstrip those of any human in power.
Billy Buyo: Yes, I do plan on bringing in demons that are more on Naruto's and Akane's level. Right now I haven't because the story is only just getting started. Eventually, I plan on adding more and more demons, each one stronger then the next, who will force Naruto and Akane to really fight for their lives.