- "Sometimes I worry about you, Bevvie. Sometimes I worry a lot!"
- ―Alvin's most common catchphrase
Alvin "Al" Marsh is the widowed spouse of the late Elfrida Marsh and the insane, abusive father of Beverly Marsh in the Novel It. Like Butch Bowers (Henry's dad) and Eddie Corcoran's stepfather, Richard Macklin, Al occasionally abuses his daughter. Unlike Butch and Richard, he tends to beat and molest Beverly for odd reasons. While beating her, he constantly tends to say "Sometimes, I worry about you, Bevvie, sometimes I worry a lot."
He abuses Beverly and her mother (who later died) and acts misogynistic. He hates it when she hangs around with boys. He is last mentioned during Beverly's childhood as trying to kill her out of anger to Its influence. He is also a form that It uses to frighten Beverly since she is afraid of him. In the novel and the miniseries, he dies of unknown causes, possibly he was eaten by It. In the 2017 film, however, Beverly seems to kill him while he attempts to rape her (however you can hear him groaning later on hinting he is alive). It is also heavily implied in the novel that he was sexually attracted to his own daughter.
However, there are times when Al proves to be very loving and affectionate towards Beverly. He died from unknown causes in 1980. He also appeared as one of Its manifestations, taunting Beverly into getting out of Derry.
Cary Fukanawa's Alvin
In the 2015 to 2016 scripts of the film, Al's character hits most of the beats of he does in his novel version- At least, he comes off that way. In his mind, anyone who lives under his roof is his property. And so, he treats Beverly with that mentality. This later leads to Alvin attempting to rape Bev, resulting in what would later be formed into the scene where Beverly beats him over the head with a toilet tank lid.