Though e-sports were around for about a decade before Riot Games was born, no company has jumped in with the same intensity. Riot controls every aspect of the professional league, right down to the music composed for live events. It runs tournaments worldwide, with its own slick broadcasting operation streaming to various Internet video sites, complete with color commentators and highlight reels — a kind of ESPN for gamers. The company also keeps a few hundred professional players on salary, ensuring that they can spend up to 14 hours a day practicing, the time required to compete at the highest level. Today, according to SuperData, a market research firm, League of Legends has more than eight times the number of active players as Dota 2, its closest rival in the genre known as multiplayer online battle arena.

Yet despite ticket prices of $15 to $50 for seats at league events, the league itself is a money loser. The tournaments function as marketing to bring in new players and to inspire loyalty in regulars, says Marc Merrill, a Riot Games co-founder and the company president. The goal is to inspire enthusiasts, doing for LoL what LeBron James and other stars do for basketball.

Which is just the first reason that Riot Games’ business model sounds insane, at least initially. The second is that the game is free to play and can be downloaded from the Internet, with no special hardware required. And players can’t buy extra power or skill for their online avatars, known as “champions” in LoL parlance. In other words, you could play League of Legends for years and never spend a nickel.

What the company sells to anyone playing the game — and, for the moment, it sells them nothing else — are game enhancements and goodies that cost less than $10 apiece. This may not seem like a path to riches, but if the player base is big and riveted enough, it is. The company says there are now 67 million active monthly players around the world, and in August alone this crowd spent $122 million, according to SuperData.

“Whenever I talk to executives at Riot, it’s like a mantra: ‘Revenue is second, the player experience is first,’ ” said Joost van Dreunen, chief executive of SuperData. “The paradox is that by putting revenue second, League will be one of the very few games to bring in $1 billion in 2014.”

$2 Here, $7.50 There

Riot Games’ offices are spread around three buildings in an industrial park, and in a handful of satellite offices around the world. About 1,500 people work at the company, most of them in the Santa Monica location. The place looks like a snack-filled haven for young slackers, with lots of employees in flip-flops and T-shirts, but attention to detail defines the company. One wall has a list of dos and don’ts for presenting Riot’s logo, a clenched fist. “The fist should never look like it’s passive, retreating or hanging on for dear life,” is among the don’ts.

Another sign of mindfulness: The window shades along walls facing east are usually drawn, even on a recent sunny day.