The Person Who Was Not Able to Become Spirits of the Dead is the 16th overall chapter of Tegami Bachi Manga
Memories are shown of Hunt, especially when he and Sarah encountered a gaichuu, to which, Gauche Suede with Roda saved them. In the memory, they saw a man appear to Gauche, calling himself, "The Man Who Was Unable to Become Spirit."
This man was preaching to Gauche about turning his back on the government, that he was being used, that Sylvette's legs are paralyzed for a reason, etc. The strange man also extended an invitation for Gauche to join Reverse—to which, he declined. After that, Hunt and Sarah began preaching about Reverse, The Man Who Was Unable to Become Spirit was Hunt, the government is actually bad, etc. The memory concludes.
Soon, Sarah hugs Lag before Niche with Steak drop in on top of Lag asking him what has happened. Lag calms her down. Connor takes Hunt and Sarah back to the Bee Hive where Dr. Thunderland can examine them. Meanwhile, Lag and Niche decide to walk.
While Lag was wandering around, he thought about his mission, especially it not being a success. He didn't encounter the true One Unable to Become Spirit, so the letter was not delivered. Lag's arm is suddenly grabbed by a Marauder that says he will collect the letter that Lag is holding. To Lag's shock, this man looked like Gauche.