Author: Atarah al'Norahn
Merk is a character from stories that are told by gleemen, such as Thom. Apparently, he was a giant who fought against Mosk with spears of fire. The stories come from the Age before the Age of Legends. Thom wonders if it ever really happened (TSR, Ch. 20).
According to the website "Seven Spokes", Robert Jordan has confirmed that Merk refers to America, Mosk to Moscow, and the spears of fire with which they fought to nuclear missiles (http://www.sevenspokes.com/chronology/1st.html).