Mr Schuler first joined the All Blacks in 1989, and said after the addition of Lomu in 1994 he knew his contribution would be "pretty devastating".
"We thought he would be a big guy you would need to contain, but you felt pretty confident having him on your side. He evolved in that 1995 World Cup, he could do things other people couldn't do, he had this combination of timing and instinct," Mr Schuler said.
The first training camp the two men had together as part of the All Blacks team was held up in Warkworth, where Mr Schuler saw evidence of Lomu's sheer power. Lomu had come up with a new move that the team was trying out and Mr Schuler found himself almost on the receiving end of Lomu's brute force.
"I'd just given the hit pad to Paul Henderson and they ran his [Lomu's] move. Jonah hit Paul Henderson, and it would have been about four metres before Paul hit the ground," Mr Schuler said.
His first thought was, "man there is no way we could lose this World Cup".
Mr Schuler found out the news about Lomu through a text from his wife.
"It's terribly sad," Mr Schuler said. "You knew he was unwell but just the suddenness was a shock."
He last saw Lomu a few years ago at a Counties rugby game.
Mr Schuler said the rugby great seemed "pretty well and on top of things".
"He was an incredible New Zealander," Mr Schuler said.
"He's leaving behind a young family - that's incredibly tough but I hope there is plenty of support out there."