PsyChotiX556
It would be good if he left the group as what we are reading right now is just original with an extra character named Mason who is stronger then ash and he knows what is the plot but he still chooses to stick around them when he knows that the group is trouble magnet and he is being held back plus if he staying for being part of cannon, it's not practical as there is no reader or audience in that world that will think wow there is new character with protagonist unless Mason breaks 4th wall, there are not many new things other then ash being more mature and Mason himself is like nanny for him and Mason needs to grow up, in this world its totally normal for there to be people with different thinking he can't get physical with everyone and that anger issue is also bad he needs to know that, world is like a coin that has two sides just because anime showed bright side doesn't mean it does not have dark side and dark side is equally important for a world to develope.
Nice to have you back again!! Please don't go too dark with the direction you are going. The Pokemon series was originally, & still is, very light & fun. That said, I'm fine with & really excited by fanfictions that choose to make it more mature, realistic, & take on different perspectives. HOWEVER, I DO NOT LIKE WHEN THEY GO TOO FAR!!! So PLEASE be careful with how far you take the dark plots.