A group of professional video-game players based in Tampa Bay have been quietly making a living — and raising a fortune for charity — mostly by playing video games and letting people watch.

Cory Michael, 33, Ben Bowman, 31, and Kevin Murray, 35, better known as KingGothalion, ProfessorBroman and kmagic101 to the thousands who watch them play video games every day online, are the founders of GuardianCon, a video game convention coming to the Tampa Convention Center this weekend.

The physical event will bring some of the most famous names in video games to Tampa, including the world's most popular Twitch streamer, 27-year-old Tyler Blevins, who plays under the name Ninja. His recent Fortnite Battle Royale game against celebrity guest Drake smashed audience records.

Meanwhile, the convention's namesake, weeklong online gaming marathon is already under way at twitch.tv/guardiancon. Through that link, people can make donations to St. Jude Children's Research Hospital as they watch various gamers take shifts playing games 24 hours a day. The marathon has raised $1.8 million for the hospital over the past two years, and is on track to hit its goal of an additional $2.7 million in 2018.

The GuardianCon founders earn their living mostly by livestreaming Destiny 2 gaming sessions from their homes in Tampa, Odessa and Land O'Lakes on Twitch, the video-game streaming site acquired by Amazon for $1.1 billion in 2014 (Murray, a.k.a. kmagic101, is partnered with Mixer, Microsoft's Twitch competitor).

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They're part of a wave of gamers forging careers as broadcasters on the platforms, where some viewers pay a monthly fee the gamers get a piece of. Personality drives viewers as much as gaming talent. On Twitch, the gamers' faces appear on-screen in a small box as they narrate and reply to a continuous scroll of viewer comments. The world of the game, as they play it, takes up the rest.

A recent New York Times article put the income of Ninja, Twitch's top broadcaster, at $500,000 a month. Tampa's Michael (KingGothalion) and Bowman (ProfessorBroman) don't have Ninja's millions of followers, but they are among the top 100 broadcasters in paying subscribers, according to several rankings. That's big, considering Twitch claims 2.2 million unique broadcasters every month.

Bowman and Murray were lured to Florida a few years ago by the state's lack of income tax. They ended up in the Tampa area specifically after Michael, who grew up here, recommended it. All three originally met online playing Destiny.

"Florida was just a better economic environment, with a lower cost of living," said Bowman, who moved from St. Louis. "And we knew Tampa was cool because we heard about it from Cory."

In 2015, they decided to get together at a bar in Tampa to meet other streamers and a few fans in real life. They planned for 200 people at Miller's Ale House on Dale Mabry Highway, but instead got more than 1,000 just from word of mouth.

Surprised, but motivated by that turnout, they debuted GuardianCon at the Florida State Fairgrounds in 2016. They hit their 3,000-person capacity and had to turn away more than 1,000 others. Last year's larger event brought out 7,000, and this year, GuardianCon's first at the Tampa Convention Center, will bring at least 10,000 attendees, Bowman said.

Aside from Ninja and the event's founders, dozens of other popular streamers and industry influencers including DrLupo, NepentheZ and Ellohime will be there playing live for an audience, meeting fans and taking part in panels.

The main stage will host live tournaments and presentations, including one on the evolution of gaming as a spectator sport, plus an EA Sports FIFA 18 exhibition and Fortnite and Realm Royale charity blitzes. Game developer Bungie, the creators of Halo and Destiny, will be there to premiere a new gameplay mode.

There's also a gamer lounge with classic arcade machines, tournaments for prizes and live podcast recordings, including a discussion on gaming and mental health, plus many industry exhibitors and vendors.

The convention is, by far, Tampa Bay's largest event devoted to video games, and its growth is reflective of what's happening in the entertainment industry. Video games now make more money globally than movies or music.

"Having Ninja in town is right on par with any other massive celebrity being involved," Bowman said of GuardianCon's biggest celebrity guest. "He's gaming's first crossover star. He's like the Rock, the way he crossed over from wrestling to acting and everything else. Ninja is on MSNBC, he's gaming with Drake, he's signing partnerships with Mark Cuban, he's breaking every record."

With the millions it has raised for St. Jude, GuardianCon also is one of the biggest gaming fundraisers in the world.

"It came from saying, we have this community now, how can we do good?" Bowman said. "And this is the first year we're thinking beyond just being something that gamers are proud of, but thinking of it as something that all of Tampa can be proud of."