LAS VEGAS — He believed he had played the main event of UFC 278 like Hermes, the god of gambling, by laying a chunk of cash on welterweight champ Kamaru Usman to defeat Leon Edwards in Salt Lake City.He had concocted other bets on Aug. 20, 2022, and tied them to Usman, in round robins and parlays, and all of those other plays had won. The entire day funneled into five five-minute title rounds inside Vivint Arena.For four rounds, Usman ruled.‘‘And I had multiple dollars of closing-line value on Usman, so I felt very strongly about it,’’ our subject said. ‘‘I was very happy. Usman dominated the first four rounds. The live line basically broke the algorithm, something like minus-1 million.’’He was poised to win more than $30,000.Instead, out of nowhere, Edwards landed a kick on Usman’s coconut with 58 seconds left to send the champ’s consciousness into oblivion. Our subject lost more than $10,000.He had been watching the event at home, outside Denver, with his girlfriend at the time.‘‘I couldn’t even get mad,’’ he said. ‘‘Almost more stunned and sad. I was in the process of building a bankroll. I would have been on the fast track to being in a more comfortable place, being able to bet larger units, all that stuff.’’She tried mollifying him. Numb, he told her, ‘‘I’m just gonna need some time alone to process this.’’ He felt as though he had been kicked upside his head by Edwards.‘‘She left me alone to do that.’’Nailing DukeOur protagonist is 26-year-old Bryant Junior, an alias he has been assigned to describe, without repercussion, how a professional sports bettor operates and thinks.The pseudonym is derived from, first, the NBA legend he had idolized and, last, the fact that he is the son of one of the 100-plus dear friends I made in the Sigma Phi Epsilon fraternity at San Diego State in the mid-1980s.In fact, I saw his father (let’s call him Hugh) in March. Hugh informed me that his kid had been doing well betting sports.I was dubious, knowing bettors like to crow. Very few can support themselves solely via betting on sports. Hugh was concerned about this murky world in which his only son had immersed himself.After eight months of discussing parameters of a potential interview, I spoke with Bryant, at length, early in the afternoon of Nov. 21.That day, nothing blinked on his radar. However, he had circled Duke basketball the next day at Arizona. The Wildcats were narrow home favorites, and the Blue Devils had unraveled at the end of a defeat to Kentucky.‘‘Duke is a top-three team and undervalued because of that loss to Kentucky,’’ Bryant said. ‘‘Kentucky is at least a top-10 team, if not top-five, so it was counted against [Duke] too much. Arizona isn’t close to [Duke], talent-wise.’’He favored Duke by 6 1/2 points on a neutral court. Mix in a typical home-court advantage, and he figured getting the Blue Devils plus-1 1/2 points represented at least 4 1/2 points of value.The Blue Devils won, 69-55.Plus-EVIn Southern California, Bryant first opened an offshore account when he was 16. It was easy to make that sportsbook believe he was 21, the minimum age required to conduct such business in distant lands.When Bryant actually turned 21, he checked his lifetime ledger. He was up 88 cents. He laughed.He had earned a degree in business marketing at San Diego State but was rudderless. A year working in operations at Amazon in Arizona turned into a 2021 move to Colorado to pursue sportswriting.The Centennial State had launched legal sports betting in May 2020, and Bryant deftly switched gears because the reward for intensive research could be so much more lucrative.NBA sides, totals and player propositions make up his wheelhouse action, so Underdog’s NBA site on X and the Unabated channel on Discord are vital to him.Bryant made about $15,000 from what he dubbed ‘‘The Draymond Green Fiasco.’’ In January 2022, the Warriors forward aimed to go straight to the bench after opening a game as a starter.It was a ceremonial nod to Klay Thompson, returning from a long injury absence. Seven seconds after the opening tap, Green fouled a Cavalier and made his way, with a previous injury of his own, to the bench.Books lost millions of dollars in bets associated with Green under wagers.‘‘If something like that happened today,’’ Bryant said, ‘‘instead of making $15,000, I’d probably make more like $250,000.’’Tennis and baseball (through the All-Star break) also get his action. The day before we chatted, he logged $813 in profit.Ultra-discipline helps him make six figures annually. In a text message, popular gambler Bill Krackomberger said the percentage of people who can make such a claim is much closer to zero than one.Bryant relies on positive expected value, which is the probability of cashing on a bet being higher than the odds implied by its price, taking into account vigorish, correlation, unit size and other factors.‘‘With gambling, people first think of risk,’’ he said. ‘‘If you manage your bankroll properly, with the unit system, and are disciplined with that, as long as you stick to being a ‘Plus EV’ bettor, you’ll never be in serious danger of losing your bankroll.‘‘People never fully understand it, but that usually helps.’’An intriguing chapterBryant moved to Colorado when it had more than 30 operators. Today, he can ‘‘get down’’ at maybe four shops, which has forced him to implement five offshore ‘‘outs.’’ He raved about Circa’s professionalism and service.He has followed Massachusetts proceedings, in which politicos are learning about the many operators who limit so many successful bettors — their constituents — or ban them altogether.The European ‘‘ban or bankrupt’’ model is invasive, and Bryant hopes ignorant politicians — he includes Colorado Gov. Jared Polis — follow the Massachusetts lead.He has made four-figure wagers, only to be told the max on his next bet is pennies. He keeps graphs, little dots that represent the profit (or loss) of days, weeks, months. A trend line connects all of the minutiae.“There will always be variation day-to-day and week-to-week,’’ Bryant said. ‘‘But as long as that trend line is tracking well, then there’s no reason to get overly discouraged, upset or elated.’’In July and especially August, he hibernates, spending time on Maui or Kauai or on the Mexican or Southern California coast.He informs others of his vocation less frequently because it’s challenging for commoners to comprehend the methods. He’s generally private and doesn’t like to brag, anyway.I found him thoughtful, precise and deliberate, an intriguing chapter for a sports-betting book. Twice he mentioned Imposter Syndrome, the psychological pattern of feeling fraudulent, despite achievements or bank-account figures.‘‘I’ve done very well for myself — and I’m very thankful for that — but sometimes it doesn’t feel real,’’ Bryant said. ‘‘I’ve been able to make such a good living this way. I try to remind myself that it’s very hard to do what I’ve done.’’