My theory about the beginning of the manga: At the beginning of the manga, a house in the jungle is shown with cups in the form of snakes. Red says that she doesn't like the hot wind, but now maybe something will change. She's covered in blood and has a gun. And also white feathers. Maybe the letter about the end of the war was brought by white birds (as a symbol of peace), but because of the war, the Reds kill them with an ordinary gun, since she is no longer a military man. After that, she finds and opens the letter with the medal. She understands that the war is over, and Ryus will finally be able to give an answer. Red has a suitcase and a bag, she is going to the jungle to see Ryus. She is waiting for an answer from her, and therefore hopes that now she will like the jungle. That house at the beginning is Ryus's house, not Red's.