In English, saying "because we're friends" can sound casual. In Japanese media, is often a heavy, emotional declaration. It implies a deep bond, a shared history, or a boundary that a character is afraid to cross (especially in romance stories). 2. The "Relative" Shield
(the likely inspiration), the protagonist Hodaka is a runaway dealing with a troubled home life. The original light novel and early drafts dive much deeper into that isolation than a 90-minute film ever could. 2. The Nuance of "De Nada" shinseki no ko to wo tomaridakara de nada original better