Especially if you throw in a little bit of mischief. Rose only had one friend growing up- Tony. Tony had quite a few acquaintances, but never any friends when he was a kid, except Rose. What would happen if The-Girl-Who-Lived and the Merchant of Death were best friends? This fanfiction, obviously. Tony Stark x Fem Harry Potter Mature for language- mainly in later chapters but there's definitely a bit in the early ones.