Vaillants translates to "valiant ones" or "brave ones." It's a strong, somewhat formal word that isn't used in everyday French slang, making it stand out in a rap context.
In the song, Kofs uses it to describe his crew, saying, "Dans l'équipe y a que des vaillants" (In the team, there are only brave ones). This highlights loyalty and courage within his circle, giving the word a powerful and authentic feel within the song's narrative.
"Capitaine" is Kofs staking his claim as the one setting things right in French rap. He raps about the neighborhood that shaped him: dealing hash from Ketama, dressing in Gucci and Dolce & Gabbana, and staying loyal to the block while calling out the snitches around him.
The emotional core sits in the hook: giving everything to people who were never satisfied, and the pride and cost of coming up through hustling and street life, right down to a friend's guilty plea in court.