SamnEric

Sam and Eric or Samneric are the only set of twins on the island. They always are with one another and have a strong bond. They play an important part in the book and with the beast. They represent reliance and unity. They are so close that they basically become one human being.

Importance
One night when Sam and Eric are up on the mountain presiding over the fire, they see a dead parachutist crash into a tree near them. But they dont know it is a parachutist so they assume it was the Beast. They tell the group and they have a meeting about it. Later they are the only bigguns besides Piggy to stay with Ralph and await for rescue. They get captured by Jack and our tortured to the point where they fear Jack and join his side unwillingly. They warn Ralph later about the Hunters coming to get him the next day after Piggy dies. Roger tortures them to get Ralph's location after the Hunt began.

Resources
http://www.cliffsnotes.com/literature/l/lord-of-the-flies/character-analysis/samneric

http://www.shmoop.com/lord-of-the-flies/sam-eric.html