Dungeons and Dragons/ Gate: Jieitai Kanochi nite Kaku Tatakeri story idea

As I was playing the Neverwinter MMO and both watched and read the manga of Gate a story crossover for a crossover story came to mind. However it will be a different story with a new gate opening up in America somewhere ( I know its cliché and its been done before in other fanfics).

However my story idea is a little different with that Loth the evil demon goddess of the drow wants to expand her evil and enslave another world and she finds a way to open up another gateway and sends her drow followers to conquer and invade said world which is Earth. At first it won't focus on the American military but on a OC character that the drow successfully taken as a slave. The captured citizen is lucky because that one of the drow "priestesses" is actually a harper spy because she infiltrated the "priestesshood" to gather information about the drow plans because the drow have been up to something and nobody knows what. When she see's the victim of slavery she rescues him by pretending to buy him to help set him free and help him get home with the aid and protection of the harpers. Over time he learns to speak drow while he's in the Underdark and eventually common on the surface.

He travels around faerun (or however you spell the name of the continent) with the aid of the harper drow spy he travels to notable locations such as Waterdeep and other locations. Meeting famous characters such as the dwarven king Brueonor Battlehammer, Drizzt Do'Urden, Regis. As well as characters from the Neverwinter game such as Sgt. Know, Lord Protector Neverember just to name a few.

I would like to add a little twist to the story where he gets abducted by a Thayan witch who is very vain and tests a spell on him before she attempts to use it on herself. The spell makes him a child again around the age of 10 years old. There is no way to reverse the spell and the only way to undo it is to grow up again.

If anyone who has a lot of knowledge about D&D story line and locations are interested this is my story idea. I don't know enough to do this story any justice and please pm me if your interested. I can help add story ideas I've done it before with another story on the site.