the boy who goes missing is the boy with the mulberry coloured birthmark on his face
Simon goes missing after the fire in "Lord of the Flies." The boys mistake him for the beast and end up killing him during a frenzied ritual.
The first littlun goes missing in Chapter 2 of "Lord of the Flies." His disappearance foreshadows the darker events to come on the island.
When the signal fire goes out
The boy who was talking about the "beastie"
he boy with the mulberry colored birthmark goes missing, we never learn his name however.
The signal fire went out when Jack made Samneric leave the fire duty to go hunting. It also goes out when Samneric "see the beast".
The first littleun to go missing is a shy little boy with a birthmark on his face who was the first to claim that he saw a "beastie." He went missing in chapter 2 when the boys lit their first fire. Piggy noticed that the boy was gone and everyone feared that he could have accidentally fallen in the fire. They quickly forget about the boy. And we are never to find out what happened to him. Hope that helped :)
Wayne Lord goes by Lord of the Flies.
Jack and his tribe of hunters were responsible for moving the fire in "Lord of the Flies" as they prioritized hunting and their own desires over maintaining the signal fire for rescue.
He is wearing clay and blood
The hunters accept the responsibility of the fire.
The fire was dying out
to go hunting