Question: are rogue and gajeel brothers?
Answer: Gajeel says that Rogue was his disciple. According to the Fairy Tail wiki, Rogue is also Gajeels sworn younger brother but the wiki doesn't say how it got this info about the brother. ... During his time in Phantom Lord, a young man named Rogue Cheney, known as Ryos, was Gajeel's sworn younger brother.