This is a bungo stray dogs Fanfic/ headcanon. Oda wrote letters for Ango and Dazai because he had a feeling he was going to die soon. Chapter one is Angos letter and chapter 2 is Dazais letter. Also to clarify in chapter 1 where it says "I got so concerned I started making you those bentos" it's one of my head cannons that Oda started making Ango bento boxes to take to work and eat.