Nicknamed "Poto" - the Maori word for small - by his schoolmates, Iro was so slight his father Kevin, who enjoyed a storied league career in England, reckoned his son would have had more luck carving out a profession as a jockey.
Eventually Iro shot up and filled out and now stands at 186cm and tips the scales at 97kg.
But the 25-year-old, who will start at left centre in Friday's preliminary final with the Storm and remains one of the NRL's smaller outside backs, compensates with his sharp turn of pace and explosive power close to the tryline.
The Sharks centre developed those attributes playing in the cut-throat brutality of league in the Cook Islands, where it wasn't uncommon for a 10-year-old Iro to fill in for the under-14s side at junior club Arorangi Bears.
"I feel like that made me more brave, I wanted to take on the big fellas and test myself by tackling their best player or their biggest guy," Iro told AAP.
"When I did that it felt good and everyone would cheer because I was the midget.
"I was tiny, bro - I'm not too tall now but at school everyone used to call me 'Poto'.
"I might have been 16 when I played A-grade but I heard my stories of my grandad playing against men when he was 13.
"Everytime I would play A-grade I'd get smashed ... you would love to watch a game there because it's so aggressive and everyone's trying to rip each other's heads off - it's a bit like Papua New Guinea."
Iro has proven a lethal attacking weapon for the Sharks since his debut in 2022, scoring 17 tries in 37 games.
He likes turning up to work at Cronulla's modest Shark Park and says he and his teammates refer to themselves as being a team that comes "from the trenches".
But it's the work on the other side of the ball that Iro loves the most, the Sharks having rediscovered a hard defensive edge ahead of Friday's meeting with a star-studded Storm attack.
Across their last 10 games, where they have lost just once, Cronulla have conceded an average of just 14 points.
"We're working hard for each other, it's a connection that we've been building and we should be pretty proud of our last couple of performances," Iro said.
"We found our confidence and we've been playing with it, I feel like that has shown a lot."
