I found the last letter (what I hope to be the last letter) extremely touching. The sweet, childish hope of it... "My dearest friend, When we were children I dove into this pond. Now we are both very old, and tired of exploring. I shall wait for you in the water, but you do not need to hurry; I can hold my breath forever!"
I nearly cried, especially when I saw his skeletal, octopus-like form, floating and glowing... He was no longer the dear childhood friend who jumped into a pond. He was one of them, and I would never get my friend back. All I could do was collect the letters he left for me, and treasure them, and hope that some day someone else would find them, and think of us... Or perhaps that, somewhere, deep in his mind, my friend still knew me. Perhaps he even knew that I had gone looking for him, and that he had waited for me for many of his years.
But deep down I know that he does not. The day my dear childhood friend jumped into the pond we once fished in was the day I lost him, and the day I followed was the day I lost myself.
Towards the end, I forgot what sunlight looked like; the only light I knew was the soft glow of the fish, and of my friend of long ago; the only memory I kept was that of a letter from one I dearly loved, and missed.
I will never forget my friend. But he forgot me a long time ago.