Limpy (The Girl Who Died)

"Limpy" (nicknamed by the Twelfth Doctor) was a Viking who was trained to be a warrior to fight the Mire. He is the villager responsible for blowing the horn as the raiding party returned from their trip.

Biography
After the Mire abducted the village's warriors and Ashildr had declared war on them, "Limpy" was one of the ones who was chosen to train with the Doctor to become a true Viking warrior.

Later, when Odin arrived with the Mire in tow, "Limpy" was partying with the others when (according to the Doctor's plan) Einarr activated the electric eels and Ashildr, through a Mire helmet, projected the image of a dragon attacking the Mire. This scared them off, and the village celebrated over their retreat. (TV: The Girl Who Died)