Dominic and Donald (real names John Shackley and Jacob Shackley), also known as the "Shackley Brothers" are conjoined twins (specifically, one person with two heads). Together they are Preachers / Proponents with the Cult of Ecstasy. Each head has their own personality and opinions.
Lust from Beyond: Prologue (Spoilers)
Lust from Beyond (Spoilers)
The brothers survived their encounter and are still part of the Cult of Ecstasy in 2021. They are once again playing chess against one another when Amanda returns with the baby Vorh'n and commands them to go to the Ritual Hall. Donald expresses some insubordination, while Dominic is eager to obey the Queen.
Later, Amanda tasks Victor to go to the bathroom and get medication for Bobby. Unfortunately, Victor enters the bathroom to find Dominic and Donald on the toilet because either the bathroom door does not have a lock or the brothers do not lock the bathroom when they're taking a dump. Donald is enraged at Victor's entry and tells him to get the medication and leave. Later, as revenge, Donald steals Sabinian's Scarlet Lodge mask and hides to jump-scare Victor as he's climbing up the stairs.
Victor must deal with the brothers one more time as he's trying to find someone to help him rescue Lily. The brothers refuse to help him. Jonathan agrees to help him and concocts a plan involving wearing Sabinian's Scarlet Lodge outfit as a disguise. Victor must then somehow reacquire the Scarlet Lodge mask from the brothers - he can trade for it by giving up Mabel's herbs, or he can steal their room key and take the mask from there.
Eventually, Mabel confides in Victor that the Cult follows Amanda as they all felt how incredibly powerful she is and fear her, with the exception of Donald as he is too stupid to realize her power. While Victor is searching for the Mask of Ughro'ecna, Mabel convinces the brothers to search Amanda's room and rebel against her, an act which earns them death at the hands of her child.