QDubs (real name: Quarter Water) is a character and a gangster. He is the cousin and second in command of RSK leader Rolla.
He is portrayed by Marc John Jeffries.
Other than being a member and second in command of the RSK, not much is known about QDubs or his past life. However, after the death of his cousin Rolla at the hands of Ghost, QDubs took over as the leader of the RSK gang. He later met up with Ghost to discuss things going on with the drug business and the changes after Rolla's death, which seem to have ended pretty well. However, QDubs later had a confrontation with Tommy and Kanan, which got out of hand as QDubs didn't trust them or Ruiz and his gang as he found out who killed Rolla. QDubs and his men were then killed by Kanan and Tommy.
- 50 Cent, the executive producer and the one who plays Kanan, commented that QDubs is a younger version of himself.
- QDubs' real name was revealed in S2E2.