Ratu has arrived from Sydney where he has been playing in the Shute Shield club rugby competition for Eastern Suburbs.
The winger had previously spent time with the ACT Brumbies and gained invaluable experience as part of their Super Rugby squad.
The 23-year old's roots are in Rugby League having spent time at NRL teams the Bulldogs and West Tigers.
He then moved to Canberra to study a bachelor of psychology with a major in nutrition at the University of Canberra where he took up 15-a-side rugby and quickly got recognised by local clubs and then the Brumbies. He then went on to train with the Australia sevens squad.
Standing at 6ft 3in and weighing in at over 100kg, Ratu used his size and pace to score seven tries in ten appearances for Eastern Suburbs last season.
His older brother Peni also has a rugby background, having played in the NRL for West Tigers, St. George Illawarra and Sydney Roosters before making the switch to college football in the US with Baylor University.