Request Book/ Idea book

Avatar Harem x Male reader

First off, don't judge me if this isn't a good idea. It's a little different than the norm. 

Well, to begin with, the main character Y/N is a serious/emotionless kid, a thinker as they call it. In fact, he didn't come from the world of the avatar, but our world. He was somehow transferred to their world and a strange ability called Transmute(basically the ability to modify/transform objects or materials in his hands) Anyway, he crashed into Aang, Katara, and Sokka when he fell from the sky above them. As he hangs out with them, he starts to lose his serious face, which is replaced with the face of joy. He even fell for a couple of girls as well as them.

His personality is emotionless, dark humor funny, sadistic, and a very intelligent person. You know, he's a bit scary and not fully trustful. But, he'll soon trust them as well as him. Katara is faster than others. Toph isn't in yet. They are still traveling to the South tribe or North? Not sure, but Aang needs to learn water bending.

Now for his ability. 

To be able to transform his target, he needs to understand the science behind it. Like a Gun. To create it, he has to understand the capabilities of a gun, how to make it, and a few other things. I want to say this is Earth bending, but at the same time, it isn't. Oh, yeah a few weaknesses. He has a phone that as unlimited wifi, and unlimited battery. It wouldn't be fair for the world of Avatar. Now, it can't be used on any living object. Also, It takes time a fully create it.