The Twitter account for “The Lightning Thief: The Percy Jackson Musical” has more than 50,000 followers. Ashlee Latimer knows them better than most.

She knows their names and handles, their inside jokes, their favorite Percy fan theories. She knows which follower is a massive Taylor Swift fan, and she knows that a delegation of Norwegians loves the musical. When she posted a tweet with a pair of cryptic emojis, a wink to a lyric on the then-unannounced cast album, she knew exactly which sleuthing follower would reply within minutes and crack the code.

But the show’s fans know next to nothing about Latimer.

They’re plenty familiar, though, with her alter ego: Mx. Thief, the gender-neutral alias posting memes and motivational notes on the @LTMusical account since the show’s run Off Broadway in 2017. Mx. Thief has become a carefully crafted and recognizable voice — in some posts mysterious and teasing; in others, urging followers to spread kindness. Sometimes, Mx. Thief is straight sass, a camp counselor crossed with an older sibling, calling out trolls, or professional theater critics.