I wanted to say a few things before I started:
1. kenji is not going to be a saiyan, or anything he is just gonna be gaining the powers of a saiyan and he is not gonna be as powerful as one either. the super saiyan forms will only be multiplying the strengh he already has, not adding any more than that.
2. Kenji will not be using ki, he will be using solar radiation to use as energy to use his powers. I'll explain how in the story in the next chapter which I think will be chapter one.
3. Kenji's powers will be this: Super saiyan transformations 1 - 3, flight, minimal regeneration (not as strong as viltrumites but enough most things fatal to humans are survivable but heart and head shots are fatal, and I dont mean punches, i mean shots that cut or obliterate the head are and can be fatal to kenji), and energy blast.
4. This story is not about invincible or the other characters, Kenji will be involved with them but he will not be in most of the story only the main plot where it effects the story, basically if invnicible is their, kenji will be their. Also kenji will be introduced in the main story of invincible around the part of the story where they are putting a new Gaurdians of the Globe or (GOTG) team together.
5. I know saiyans in dragon ball rely on sezu beans a lot and I'll make up something for it, but at the beginning of the story it won't appear until more towards the middle or end of the story.