David Kelly -- known affectionately as “DK” by the Saint John Sea Dogs and their fans -- has passed away at the age of 40.

Kelly was the head equipment manager of the Sea Dogs for 13 years until he retired in 2017.

He was diagnosed with cancer in 2014 and became widely admired in the hockey world for his fight against the disease. In addition to carrying on his duties with the Sea Dogs, he spearheaded multiple charitable initiatives, including the selling of his popular Monkey Band-Aid apparel to raise funds for the Saint John Regional Hospital Oncology Centre.

“We are all saddened by the passing of our dear friend and colleague David Kelly,” Sea Dogs Owner and CEO Scott McCain said. “Nobody has shown more character and courage when faced with adversity the way DK has done over the past several years. On behalf of all the Sea Dogs organization, I extend our deepest sympathies to all his family. We will miss him.”

Kelly, who became known for his #TeamDK movement, was also on hand for three QMJHL titles (2011, 2012, 2017) and one Memorial Cup championship (2011).

"He's a guy that battled through so much and he always wanted to stay positive and he wanted to come back," said Ottawa Senators star defenceman Thomas Chabot, who played for the Sea Dogs for four seasons. "He was at the hospital the year we went to the Memorial Cup (in 2017) and somehow he made his way to Windsor with us.

"It just shows how much he cared about the Sea Dogs organization and the people. He's been through so much and he's trying to help everybody else other than himself. He was just focused on making others happy and it just (showed) how much of a great person he was and to see him go is very sad for all of us who knew him really well."

Chabot remembered Kelly as one of the first to welcome him to Saint John.

"When I got there, I barely spoke any English and he always made sure everything was fine for me," he said. "I didn't know the person and he didn't know me either, but he always made sure that anybody that was coming through the doors or was drafted by the Sea Dogs got a warm welcome and he was always willing to show the new guys the city and always willing to have a talk whether it was about hockey or not. ... I think that's what made him such a great guy and so respected around the hockey world. He cares about people and he wants people to do well and we're going to miss him a lot."

Florida Panthers forward Jonathan Huberdeau, who also played for the team for four seasons, paid tribute to Kelly on Twitter.

"Never seen someone fight this hard, sad to see you leave my friend, we shared some good memories together," Huberdeau tweeted. "RIP DK!! Deepest sympathies to his family."

Tributes for Kelly poured in on social media from around the QMJHL and throughout the hockey world on Thursday.

"David Kelly's passing this morning has left me with a heavy heart," QMJHL commissioner Gilles Courteau said on Twitter. "It was a privilege and honour to work with DK for over a decade. I can say that he was a proud member of the SeaDogs and 'Q' family since day one."

Before retiring, Kelly was the only head equipment manager in Sea Dogs’ history.

Before joining the city’s Quebec Major Junior Hockey League franchise, Kelly worked with the Waco Wizards of the WPHL, the Milano Vipers (Italy) and Bracknell Bees (British Super League).

He began his career in hockey as the visiting team dressing room attendant with the AHL’s Saint John Flames before earning a promotion to assistant equipment manager.

He also worked extensively with Hockey Canada’s program of excellence.

He worked 805 regular season games for the Sea Dogs before joining their front office as senior advisor to hockey operations, before leaving to pursue philanthropic initiatives.

“My fondest memories of DK are the light and personal conversations we had about our nephews, comparing notes, him sharing funny stories about Jacob,” said Sea Dogs President and General Manager Trevor Georgie. “He loved his family dearly. We are sending our prayers and love to Dominique and his entire family.”

Last December, the Sea Dogs unveiled a wall of honour for Kelly in the concourse of Harbour Station as a reminder of his legacy.

The team has announced they will observe a moment of silence Thursday before their game at Harbour Station.

-- With files from Lisa Wallace of The Canadian Press in Ottawa.