A fully fit Kane is arguably the first name on Gareth Southgate's teamsheet for this summer's tournament, a goalscorer of proven pedigree, few peers and plentiful admirers.
Without the Tottenham striker in Russia, England's prospects when taking on the best teams on the planet would surely plummet, making his recent ankle problem all the more concerning.
Leicester defender Maguire was not alone in crossing his fingers when Kane hit the deck against Bournemouth on March 11, sustaining an ankle problem that is expected to keep him sidelined for up to a month.
"When he went down I am sure every England fan, every member of the England staff, every player wanted him to get back up," Maguire said.
"Harry Kane is probably the best striker in the world. He is scoring frequently, getting the Golden Boot in the Premier League last couple of seasons and is up there again.
"I wish him a quick recovery and I hope he comes back firing goals from now until the end of the season and hopefully he will take that form into the World Cup.
"Hopefully it is good news and it is a speedy recovery."
Maguire's esteem for Kane is built not just around their time together on England camps but also personal experience of trying, and failing, to keep him under wraps.
"Harry came to the King Power (in November) and we kept him quiet for 60 minutes," he recalled.
"We thought we had done a good job then all of a sudden, he puts one in the top corner from nowhere on a tight angle and the game was back on."
The Foxes held on for the victory that day despite Kane's best efforts, with Jamie Vardy on target in a 2-1 win.
Vardy is likely to deputise for the Spurs striker in Friday's Amsterdam friendly against Holland, with Maguire also poised for a fourth international cap.
Stand-in duties may be the best Vardy can hope for in the summer too, but the 25-year-old sees that as no slight against his club-mate, who he believes is more than capable of doing the job.
"Jamie is quick but he is an excellent finisher as well. I wouldn't say it is disrespectful to compare him to Harry Kane," he said.
"Me and Vards get on really well - we're both Sheffield lads. We have a bit of banter all the time but in training it is a nightmare to play against him.
"You have always got to be aware of him. When I played against him in Hull, especially at the King Power game at Leicester away, he caused us all kinds of problems that day.
"I am sure you could speak to a lot of defenders out there in the Premier League - they would not want to play against him week in, week out."