Sam and Eric are twins in the group. They are a part of the biggins crowd. They are often referred to as Samneric, because they do everything together, breathing, laughing, panting etc., making them get taken as a single unit.
They entered the group, stumbling along the beach together, towards the sound of the conch. They were said to be chunky and vital and with hair like tow (Pg. 14). They were quiet at first, only really communicating with each other, though they have grown more outgoing they still stick to themselves mostly.
Samneric are loyal to Ralph, however, when the group begins to disintegrate, they begin to become vulnerable to the strength and manipulation power of Jack, though remaining mentally loyal to Ralph.
Their main job throughout the book (so far) was to tend to the fire. The twins are offered a certain amount of security from Ralph, however when Jack and the hunters threaten it, the twins show the weakness of human nature when pressed and will eventually turn on Ralph.