Jaynelle Jane Williams has always been Danny's better half. Everyone calls her JJ. She's not as stubborn as her brother. They've been inseparable since she was born. When he moved to Hawaii, she was heartbroken so she saved up and packed her life into many boxes and moved out to Hawaii just to be with her big brother. She's always on Danny's mind and he just accepts her as she is. She will soon figure out that her brother doesn't do the same detective work as he did back in Jersey.
Steve McGarrett, Annapolis, five years Navel Intelligence, six years with the SEALs, transferred to United States Navy Reserve, head of the Governor of Hawaii's task force: Five-O for nine years. He's Danny's boss and JJ starts falling the first time they meet. Steve wasn't trying to get serious with anyone after his last serious relationship but he might have had a change of heart somewhere along the way.