Blues coach Sir John Kirwan, confirmed he was chasing Macilai and Pryor, but missed out.
"We are excited to have Matt Moulds and Dan Bowden in the squad from Northland and to continue to work closely with the region to develop more players to the Blues in the future," Kirwan said.
"We were also very keen to sign Dan Pryor and Jone Macilai, but they have decided to take up offers from other teams. Our door will always be open and we hope to see them in the Blues in the future."
For Macilai, it is a dream come true to play for the franchise he has admired and supported since he was a boy in Fiji. "When I called my mum to relay the good news, the first thing she asked was whether I'd be playing alongside the likes of Richie McCaw and Dan Carter so I am very happy with the contract," he said.
He trained with the Blues wider training squad this season but didn't make the cut for the 2015 season.
Macilai, who has signed a two-year deal, was approached by a Crusaders' representative before Northland played Canterbury in Christchurch on August 28. His selection was confirmed by his agent after Northland's ITM Cup match against North Harbour on October 3.
The 24-year-old was spotted by Awanui coach Glen Subritzky at a local sevens tournament in Fiji in 2012 and offered a three-year contract with the Northland ITM side last year.
"The Chiefs also showed an interest in me and it was the case of which franchise signed me up first. But deep down I had always wanted to play for the Crusaders. To play alongside top players that I grew up watching on telly is a dream come true," Macilai said.
Blackadder praised the winger for his all-round skills.
"We're delighted to have him on board and the thing that really excited me about him is that he's not just a good finisher but has all-round skills of a good rugby player.
"He's got the ability to break the line, he actually goes looking for work, has genuine pace, he can tackle and clear rucks and does the basics well," the former All Blacks' skipper said.
The Blues' loss is Crusaders' gain and Blackadder said Kirwan's side had regrettably let go some promising players in the recent past.
"They also let go (Malakai) Fekitoa who turned out to be an absolute star."
He said Macilai was in the right environment at the Crusaders in terms of honing his rugby skills.
Blackadder isn't concerned about Macilai's small physique.
"He's already shown encouraging signs ... he'll do the job in terms of attacking and creating space and it'll just be a case of building on his strengths.
"When the mind's willing, the body will do the job. We've got a good squad with good depth so we're not expecting miracles from him when he comes."
Blackadder said there was every possibility Macilai would pair with fellow Fijian Nemani Nadolo on the wing, pre-season and in regular competition.
Others with Northland affiliations who've played for the Crusaders over the years include Norm Maxwell, Norm Berryman, Jake Paringatai and Con Barrell.
