Star Wars Episode VIII Theory 1 "The First Order Army Joins the Rebels to fight the Sith"
Of course I don't have any real informations to build that up but seeing Star Wars as the art of repetition this theory to me is just as possible as most theories I heard since Episode VII came out.
The clone army was ordered by the Sith Lord but started in the hands of the Republic as troops of the Jedi to fight the Droid army of Count Dooku and the Separatists. Basically two armys are build up by the same guys to get the Galaxy in a big war.
The reason for this was to make the Galaxy weak enough to get taken over by the Sith.
In the view of the audience the Army of the Clones started as good, turned to bad and was replaced by the Imperial troops in Episode IV.
The Army of the first order is from the view of morality just as questionable like the clones were back in Episode II and III.
The clones were breed without rights and just seen as property of the Republic. The First Order Army are brainwashed humans stolen as babies from their families. Even though they did bad deeds they still are victims themselves. The character Fin gives us a hint what kind of tragedy is behind their situation.
So finally after the Sith think the Galaxy is ready to be taken the "Sith Army" will show up and the remaining Rebels and Troopers will unite to fight against them.
Sounds crazy? Yes, it does but hey thats my wish for Christmas and "Star Wars Episode VIII"
So if you like to let me know what you think will happen in the next Star Wars movie please write it down in the comments below.