When Keanu Reeves walked onstage at a video game conference in Los Angeles in June, Peter Sarkisyan marveled at how the actor seemed to transcend his earthly form.

Maybe it was Mr. Reeves’s lanky silhouette, shrouded in a cloud of smoke. Or, perhaps, it was the connection he felt with the actor, who, like Mr. Sarkisyan’s mother, was born in Lebanon and donates to cancer research. But Mr. Reeves was the man Mr. Sarkisyan aspired to be. He cried out from his seat: “You’re breathtaking!”

“I thought, ‘Dude, this is me in the future,’” Mr. Sarkisyan, 33, an online gamer who goes by the name “Peter Sark,” recalled in a recent interview. “Keanu speaks truth. He’s nice to people. I just said what everyone was thinking.”

Mr. Reeves has been a cipher-like presence for much of his three-decade movie career, shifting from the reluctant hero of “The Matrix” series, which brought in $1.6 billion at the worldwide box office, to a puppy-loving assassin in “John Wick,” to a sad-looking sandwich eater who launched a thousand memes.