Craster's last son

"A gift for the gods."

- Craster's wives

Craster's last son ​is an unnamed minor character in the fourth season. He first appears in "Oathkeeper".

Background
This baby is the last male offspring of the wildling Craster, killed by Karl Tanner of the Night's Watch during the mutiny in which the old wildling was killed. The baby is born months later, while Karl and several other mutinous black brothers are still occupying Craster's Keep.

Season 4
After being told by Morag that the baby will be a sacrifice for "the gods", Karl orders Rast to leave the baby in the woods for the White Walkers to seize him. Some time after Rast abandons the baby in the Haunted Forest, a White Walker seizes him and takes him to the lair of White Walkers, deep in the Lands of Always Winter. After being left at an icy altar, one of the White Walkers' masters takes the boy and puts a finger to his face. The baby's eyes quickly turn the color of those of the White Walkers.

In the books
In the A Song of Ice and Fire novels, Craster's wives are convinced that the baby boys given by Craster to the Others are, in turn, transformed into new Others. However, no such event has ever been witnessed in the books so far.