Character Analysis
One for the Money
If we were taking things chronologically, the first story in this collection, "The Transfer," would be the first time we meet Four. He's still just plain Tobias, which is like being an ice cream sundae without the chocolate sauce, banana, nuts, or cherry on top. He's not happy about his identity or his situation, and we can't blame him. Tobias is trapped in an abusive home, subject to his father's violent outbursts, and he feels he has no way out.
But he does! This story is called "The Transfer" and transfer he does. When it comes time to choose his faction, he switches from Abnegation to Dauntless. There, he discovers that he only has four fears: heights (falling from heights to be exact), claustrophobia, his hidden violent side, and his evil father, Marcus. It's here, in Dauntless, that he chooses a new name: Four. The new name reminds him of his strengths, and helps him mentally move away from the weakness he felt at the hands of his abusive father.
Two for the Show
In the second story, "The Initiate", Four's main internal conflict is that he doesn't want to hit a girl. He almost loses his first fight as an initiate to a female, because he won't hit her.
My instincts took over, and just one hard elbow to her jaw knocked her down. I still feel guilt curling up inside me when I think about it. (2.4)
He gets over this guilt by teaching a girl named Shauna to fight. Along the way he makes friends. Aww. See, in Dauntless, violence brings people together.
Making friends is a big achievement for Four. Way back when he was Tobias (last week), his father's main tactic of abuse was isolation. Marcus kept Tobias from making friends, keeping him lonely and weak. In this story, Four recognizes his strength growing as he wins fight after fight, but his biggest strength may be in his newfound allies.
Three to Get Ready
The third story is "The Son," and in this story, Four does his best to make order from chaos. This is symbolized in the section where he learns computer programming. Here's him talking about learning to code:
Everything has to start in the right order. […] Just make sure that everything is in the right place. (3.129)
Four has to make sure he is in the right place, too, as in this section he has to choose his job. This is where the chaos part comes in. Not only does Four discover his mother, Evelyn, is still alive— gasp!—he realizes there's a plot to control the leaders of Dauntless. Although Four is on the leadership track, he doesn't want to be controlled. If we've learned anything about him at this point, it's that he wants to be in charge of his own life, not a pawn.
By the end of this story, he starts thinking about how he can make some big changes for the good of the broken society he lives in.
And Four to Go
The final of the four stories in the Four collection about Four (so many "fours," we know) is called "The Traitor." Here, Four struggles with being, you guessed it, a traitor. He wonders if he should betray his faction. He feels guilt over Al's death. And he starts getting involved in Tris's life in ways that initiation instructors shouldn't.
Basically, this is the culmination of Four deciding who "Four" really is. He chose this identity for himself, and now it's time to choose the direction he wants life to take him. Does he honor the faction he chose, does he honor the parent who abandoned him, or does he honor the girl he's beginning to fall in love with? If you've read Divergent, you know the answer. And if you haven't, then why are you reading this?
Tobias "Four" Eaton's Timeline