a/n: Spoilers for Divergent and Insurgent. Takes place post-series.

Disclaimer: I do not own Divergent.

Dear Beatrice,

I know I have done too much to be forgiven, but I do hope you read this letter, not as an apology, but more as an explanation for why I did what I did. I understand that you are Tris now, not Beatrice, the sister I knew for sixteen years, but if anything, I hope you will at least pardon me for that small slight.

We were never really close in the sense siblings usually are, were we? Sometimes I felt that I was years older than you. I was always expected to be something, and because I was older, make sure you were being that too. The duty of the older sibling is difficult, and I realize you feel as if I abandoned that. I abandoned being Abnegation, I abandoned my parents, and most of all; I abandoned my job as the older brother. All of that may appear true, but maybe you do not understand who I was.

After someone has appeared a certain way to one for quite some time, one ceases to notice the changes in them. He or she thinks of them as a set idea, and everything one notices about them otherwise seems to strengthen that idea. When the person begins to change, one does not notice, or at the very least, they deny it. Some people have refuted me on this subject, but as one who has experienced this for at least ten years of his life, I feel that I am fairly correct on this.

I did not suddenly become Erudite, nor did one event in my life greatly affect my choice. It was a slow development that pushed me to this path. You, father, and mother, as well as others, thought that I was perfect for Abnegation. I was selfless, kind, caring, and helpful; I was the one who willingly volunteered to help the factionless. And really, you must understand that I was not pretending to be selfless and kind. There was—is—a part of me that delights in helping others and seeing the bright smiles of the factionless. It came naturally to me, perhaps as swimming comes to a young fish. You, Beatrice, seemed to always push against this ideal and rebel, even if you didn't notice it, so our parents came to look to me as their darling, dependable child. (Although, if you must ask, I've always felt as if they liked you just a little bit more). I seemed to be the perfect fit for the faction.

But some people are just born with an insatiable desire to know and understand the world around them, and Abnegation is not the place to find that knowledge. The emphasis has always been about others, about sacrificing your wants and desires for the greater good. But here is the catch—on the inside, I have always been selfish. I have always held on to a part of myself that wanted the best for me. You are perhaps one of the most selfless people in that sense, that you put others before you even when you do not realize it. You still have the same will to have the best for yourself, but you try to shun it and toss it aside. I, on the other hand, fed that part. I snuck books from the school library that no ordinary Abnegation person would read, and hid them under my coat so no one—not even the librarian—would see. Often I stayed up until midnight to read. I sat just a bit too close to the Erudite table during lunch when I could; their discussions were fascinating to me and from them, I gained knowledge.

To put is simply, my life had always been a choice between two factions, two ideals, and while there were faults will both, I had to choose one. And when I watched my blood, sunset red, mingle with the clear water, I felt a sense of belonging. Perhaps you felt it as well, when your blood sizzled on the hot coals. I do not know. I am glad though, that you chose what you wanted, because at the end of it all, you will only fight for what you believe in. This was true for me, but I will get to that later.

Being from Abnegation in the Erudite faction was, as you might imagine, very hard. The concepts they base their lives on are very different, and I was looked down because I was from there. Those who come from other factions are more accepted, because their values somewhat merge into Erudite's. I was shunned, for the most part, and ridiculed. No one believed I could pass the tests. You must have felt the same. But I did get in, as number four on the list, even.

Can you imagine a world, Beatrice, where knowledge is not held back? Where anyone can walk into the library and ask for a book on a certain subject, and get it? Where is it encouraged to learn and discover and think for yourself? That is Erudite at the very core, the very root. But things have changed. Father often spoke of how Erudite was corrupt, a faction of people lusting for power. He was not completely wrong. There are many Erudite, of course, who are arrogant and condescending and power-hungry. They treat those who are less intelligent as lesser beings. One could even say all who are in charge of Erudite, at the very top, fit this perfectly. But many of the people I knew were just intelligent, curious souls, who wanted to devote their lives to the searching of knowledge and new things. I felt at home with these people. But often times the only glimpse you see of Erudite is that of the people in charge, who are—and have been for quite a while—destroying this ideal for their own power. But really, what faction does not show this? What faction is completely unchanged, completely intact will all its original values and ideas?

I loved being Erudite. But of course, that does not answer the essential question: why did I do it? Why did I betray Father, Mother, and you? Why did I stand by as you were tortured, seemingly uncaring about you? These are a few things on a list of unforgivables.

Sometime during my stay at the Erudite faction an idea began to form in my mind. Why did the world have to be split into these factions? Why did we have to pick certain ideals, and to certain things, for the rest of our lives? The more I thought about it, the more factions seemed unreasonable. There was no peace in our city. Factions turned against factions, families stopped talking to each other, and altogether, there was a sense of hostility everywhere you went. It did not create peace, only segregation, a large divide between people. How could humans, such complex beings, be categorized into four qualities? Into black and white? I kept this quite, until one day, Jeanine approached me, and asked me to come to my office. It was to speak about you, Beatrice, and your Divergence. She wanted me to tell her all about you, and constantly reminded me it was faction before blood. After she had explained this concept of Divergence to me, I did something very rash. Almost without thinking, I had asked, "But why don't these people do something?"

Jeanine had looked at me closely, and replied, "Do what?"

I stopped, realizing that there was a reason. Fear, for the officials in charge depended on people being able to fit themselves into one category. If someone realized that there was such thing as divergence, and, to a point, that everyone has some divergence in them, the whole government would crumble. Those in charge would no longer have power. I did not want to tell Jeanine this, but of course I had too. I expected her to turn on me, call me foolish and idiotic, but she agreed with me. She though those of Divergence should show the world that they were.

I do not remember what she said, but looking back I realize she had used me for her own personal gain and priorities. She had reeled me in, turned my own mind against me, and all along I never realized it.

But Caleb, you might say (You will always very brief and concise, while I have a tendency to ramble), you have not answered the question. And I haven't. But the answer to it is very simple. There was one reason I betrayed mother and father, betrayed you, and watched your torture. I was afraid. I was a coward. In my mind I had constructed thousands of excuses, but they all tried to cover the one fact: I am not brave, nor am I selfless. I would not risk anything, not even to save my sister. Do you realize how much I have agonized over this fact for the past month? It has pressed on me, covered me, suffocated me. It is something I deeply regret. Not everyone has the same kind of bravery you do, Beatrice.

My trial was two weeks ago. The vote was unanimous; the trial found me guilty. My execution is in ten days. I will never get to live in the world I dreamed of, the world where there are no factions, no divides. But you will, Beatrice, and although I know you do not consider me your brother, and have no reason to do so, I hope you will visit me one last time. If there is one thing I regret, it is betraying you. If I could go back in time and change it, I would without a blink of an eye—but alas, the past cannot be changed. I must live and die with the choices I have made.

But I want to say this, just in case you do not come. Despite what my actions seemed to have said, I love you, and will consider you my sister forever.

Your brother,

Caleb