Despite his relative youth, the 22-year-old is royalty in the world of chess -- hailed by Russian legend Garry Kasparov as a Harry Potter-type "super-talent".
Since 2010, he has dominated the World Chess Federation's list of top players, with an even higher score than his one-time coach Kasparov.
"You cannot be a number one in the world and be a good loser," the rather austere Carlsen told reporters in Oslo last month. "I'm not a good winner either," he added.
"I try not to rub it in to my opponents. Unless they deserve it, of course."
A fashion model in his spare time, Carlsen made it to the Time magazine list of the 100 most influential people in the world in 2013, even before the first game in the World Chess Championship kicks off Saturday in Chennai, India.
If he wins, Carlsen will equal Kasparov's achievement of obtaining the title at the age of 22, if a few months older.
Introduced to chess by his father, Carlsen showed off his genius as a toddler.
At the age of two, the self-taught prodigy knew by heart all the car brands and later memorised the long list of all Norway's municipalities, with their flags and administrative centres.
Sibling rivalry with one of his older sisters sparked his interest in chess, which soon led to his first competition at the age of eight.
The breakthrough came in 2004, when the 13-year-old defeated Russian former world champion Anatoly Karpov, forced Kasparov to a draw and became a grandmaster.
The Washington Post dubbed him "the Mozart of chess".
The dishevelled and serious looking teenager refused to bide his time and climbed the international chess ladder at a stunning speed.
"Magnus Carlsen rocketed to the top of the rating list almost without pause, displaying a consistency and tenacity rare in a young player to accompany his limitless talent," Kasparov said in a column in Business Insider this week.
He said of his time coaching the Norwegian in 2009: "I am no bearded Dumbledore, but it was impossible not to see Magnus as a type of Harry Potter, a super-talent destined to become one the greatest and to leave a deep mark (a lightning bolt?) on our ancient game."
But Carlsen himself said of his game: "I still have so many ways to improve. In every tournament on almost every game, I find that I make mistakes, inaccuracies".
"I definitely have some kind of talent but I don't know exactly what it consists of."
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Only the world champion trophy is missing on his shelf, and he knows he is the favourite to win it this year.
"Everything is in Magnus's hands," Karpov told Norwegian news agency NTB in August. "He's at a level where he could beat anybody, even the world champion."
Carlsen will face Anand, the holder of the title since 2007, in a 12-game contest starting Saturday.
Carlsen faces the challenge with oodles of confidence and said his Indian rival will need to be on his guard.
"He'll need to be well prepared in the opening and just keep concentration at all times, never lose focus, never relax, because then he will be punished," he said.