Warning: Slight spoilers for episode 25 (as in, it is only mentioned in one line)
"Letters to the one I love - Goodbye"
Dear Hawkeye,
I had that dream again. It's the third time this week. I keep seeing the faces of those I have killed, the people I have slaughtered. I am a murderer, Riza. And I cannot take that back. It is always there, haunting me; knowing that I killed them,I amdrowning in my sins. I love you, Riza, but I cannot live with myself anymore. Goodbye.
Roy
Dear Riza,
Everyday when you walk into the office, my heart flies. I have to turn away to keep myself from proclaiming my love in front of everyone. I am a colonel in the military. I am a state alchemist. I have been in war. And yet, I find it nearly impossible to be around you without calling out your name, embracing you in my arms, telling you how I really feel. I love it when you stay late to help me with my work, keeping me up to task, never letting me fall behind. I love it when you yell at me, slap me over the head, pull you gun out on me. I know that sounds weird, but it makes me happy. It shows that you care, that you are looking out for me. However, no one else does. I am not Colonel Roy Mustang to them. I am not the Flame Alchemist. I am merely a barrier, an obstacle in the way. All they want is to get rid of me and I am going to help them. I have given up.
Roy
Lieutenant Hawkeye,
It's over; I cannot take it any longer. My life is over, Hughes is dead; my best friend is gone. What am I supposed to do? I have no reason to be living. I have no one to live for; no one but you. Yet, because I am your superior officer, I am not allowed to love you. I am not allowed to have a relationship with you outside of the military. Any feeling I have for you are to be pushed aside. I am forbidden to love you. I'm sorry Hawkeye, but if I cannot love you, I have no reason to live.
Roy
Hawkeye,
Ever since the day I say you, I knew I was in love. Your eyes are the most unique brown I have ever seen. They are so vibrant that they appear to be almost red. You have the most striking hair. The way it shines in the light – it's radiant. Your face, the beholder of the most beautiful woman I have ever seen. I love you, Riza, but that love will never be returned. How could you ever love a man like me? I am nothing compared to you. That is why I am ending my life. I hope to one day live with you for eternity. I love you.
Roy
Riza,
I'm sorry
Roy
A single tear fell down Riza Hawkeye's cheek. Looking up, she read the inscription in the stone before her:
Colonel Roy Mustang
The Flame Alchemist
A strong soldier, a great friend, a loving man.