Besides carrying a gnarly stick with two crocodile heads as a handle (which, for starters, screams "I'm a shady guy"), Harrow also sports a simplistic tattoo on his right forearm. The piece in question is a simplistically rendered scale fashioned in such a way that aligns with the other basic elements of Harrow's definitive look; here stands a man who has seemingly let go of material possessions and is, instead, putting everything he possesses into his new faith. Think the High Sparrow from "Game of Thrones," only worse.
Unlike the tattoos shown off by other MCU characters, Harrow's scale has a special, otherworldly link to Ammit, the holy power he follows, the same way the cane does. When one of Harrow's followers requests judgment, the scales physically move on his arm, tipping in or out of favor as it senses the energy flowing from the person who is being judged into Harrow, who holds hands to begin the flow. Should the scales turn green, the zealot lives to see another day. If they turn red, they go out looking like they just drank from the wrong cup in "Indiana Jones and the Last Crusade," leaving Harrow one step closer to passing judgment across the planet in Ammit's name. Seemingly able to look at both the past and future of the follower, one person that it seems to have issues with is Steven Grant, mainly because he's not the only person being judged in that instance.