Episode IX Stories

The Teaser Trailer Part 4 The Red Forest

Then we have this really awesome scene:

This scene looks really cool to me I really love the red background. It reminds me of the throne room scene in the Last Jedi, which was one of my favorite scenes.

This scene was also part of the beginning of Ben's redemption, in my opinion. He risked his life to save Rey, he chose her over his evil master.

My hope is that this scene is his redemption. Of course from what little we get to see in this scene, it is hard to tell.
There are few interesting things I noticed in this scene
This forest has never been seen in a Star Wars movie before, so this must be a knew location.

He is not wearing his helmet in this scene, so that means that this scene either takes place before he reforges his helmet. (In which case this would not be his redemption) or he looses his helmet at some point. Or this is his redemption, and he removed the helmet because of the darkness it held. He could have also removed his helmet for Rey, as he did in the Force Awakens.
(I am glad that he is not wearing his helmet in this scene, because I saw a leak, which thankfully was false that he was going to be bald in Episode IX. I even saw concept art of it. Not good.)
I also noticed that whoever he is fighting looks like one of his knights.

Which could mean that this is his redemption, and he has to face his knights.
But it could also mean that one of his knights goes rogue.
One of my best friends, Winter Wolf, also noticed something interesting about this scene which I didn't see, and I haven't seen any theories about.

I had gif of this scene, which was really awesome but wouldn't load. So, if you watch this scene very carefully in the trailer, he doesn't stab whoever he is fighting. He just knocks them down with his arm. And he even has the hilt of his lightsaber pointed towards them, and the blade pointed away from them.
Of course the scene ends when whoever he is fighting lands on the ground, so he could have stabbed them then. But as Winter Wolf pointed out to me, why would he be fighting them that way, if he wasn't trying to keep from hurting them too badly.
I did have the theory that he could possibly be training his knights, but the shooting stormtroopers in the background would suggest otherwise.
My thought is that either the knight has gone rogue or Ben has joined the Resistance and is forced to fight this knight. But he doesn't want to hurt them.
If Winter Wolf's theory about the knights of Ren is correct, then they are some of Luke's students who choose to fallow Ben to the Dark Side. They are most likely some of the younger students, as the students who were older or the same age as Ben probably made fun of him for being different or were jealous of his power and the fact that as Luke's nephew they thought that their master cared more about him than the other students.
But the younger students would have looked up to Ben and because he was in his twenties, he probably even helped with their training. They probably looked up to him, almost like a big brother.
When Ben turned to the Dark Side, the older students, who had been mean to him in the past probably tried to stop him, so he killed them.
But when he came to the younger students who he had helped to train, who looked up to him, who he loved like younger siblings, he couldn't bring himself to kill them, so he convinced them to join him and trained them as the knights of Ren.
Ben turned to the Dark Side 6 years before The Force Awakens, which if the tweet I saw by John Boyega about Episode IX being around a year after the Last Jedi was accurate, then it would be 7 years. The students could have been between 8 and 12 years old, which would make them no more than teenagers now, between 15 and 19 years old.
And because Ben probably knew them most of his life and was probably like a big brother to them, helping to raise them, it would make sense why he wouldn't want to hurt them.
Me and Winter Wolf were discussing this theory just the other day. And I really hope that it happens both in Episode IX, and the Ben Solo prequel trilogy.