The 23-year-old fighter left for Poland yesterday where he will represent his country in Muay Thai.
Halangahu could not be reached for comment but his coach, Matt Toa, said Halangahu joined Hammerhead about 10 months ago weighing in at more than 120kg.
He is down to 89kg and is a much more nimble and explosive opponent, Toa said.
``Because he has lost so much weight he is a lot more agile now,'' Toa said.
``He was already a fast heavyweight, so he has natural speed for his division and also he is going to be a very, very hard puncher as well.''
There are eight competitors in Halangahu's division and he will need to win three fights in a row to emerge victorious.
``He is a bit of a dark horse. He is going in with less experience than his opponents. But we've done some research on his opponents and we think we can hold our own.
``We are not going there to make up the numbers, put it that way.''
The format is for three, three-minute rounds. Punches, elbows and kicks are all legal ways of striking an opponent.
The athletes will be allowed to wear elbow pads and shin guards.
Toa will travel to Poland with Halangahu and be in his corner during the tournament.
``There are a lot of Eastern European countries represented [in his division] and they have got that hard style. There will be some good fights.
``They are going to bring it and we are not going to shy away.''
The World Games is a multi-sport event first held in 1981. It features sports or disciplines not contested at the Olympics.
It is being staged in Wroclaw, Poland on July 20-30. There are 27 official sports and four invitational sports featured.
Halangahu got his opportunity to compete at the event because of a good amateur record. He has been working towards the event for the past 10 weeks.
