It's hard to prove a negative, but so far I have seen no evidence of anyone living on Blackberry Creek before the sons of Ephraim Hatfield settle there in the spring of 1816. There are certainly families nearby, possibly on Peter Creek or Pond Creek or on the West Virginia side (Obediah Blankenship is here early, as is Henry Runyon, Moses Ball, and others), but the arrival of Joseph and Valentine Hatfield and Ferrell Evans and their families seems to mark the beginning of permanent settlement on Blackberry Creek. So let me go back to 1816 and see what there is to know about that initial act of settlement.
Joseph B. Hatfield was the eldest child of Ephraim and his first wife, Polly Smith or Goff. He was born in 1785, so at the time of his arrival on Blackberry he would have been around 30 years old. His wife, Martha "Patsy" Evans, was also 30 years old. They were married in 1808, and by 1815 they had four children: William, Ferrell Marion, Ephraim, and Phoebe. Martha Evans was the daughter of William Harmon Evans and Martha Thompson. Martha Thompson's parents, John and Mary Thompson, were from Ulster, Ireland and, if the work I have seen is correct, Martha was the first of their children born in America (in 1746). Martha Thompson's first husband, William Ferrell, was also born in Ireland. He was killed by Indians in 1778 at the New Garden Settlement in what would eventually become Russell County, Virginia. Two of Martha's children with William Ferrell, John Ferrell and Richard Ferrell, also came to the Tug Valley, settling on the West Virginia side of the river.
Valentine "Wall" Hatfield, born in 1789, was the fourth child of Ephraim and Mary Hatfield (the two sons between Joseph and Valentine - Aly and Ericus - were both dead by 1810). He and his wife, Martha "Mattie" Weddington, had 6 children by 1815 - Joseph B., Andrew, John, Ali, Ephraim, and Virginia Jane. I have seen it written that Valentine was a veteran of the War of 1812 and that he received 50 acres in Kentucky as compensation for his services, but I have not actually seen any documentation to prove this assertion. He and Mattie had no children born between 1813 and 1817, so it's certainly possible that he could have been in the army during the final year of the war (1814), and it's also true that soldiers were frequently given tracts of land in lieu of monetary payment. I can at least say that Valentine may have served in the army during the War of 1812.
Ferrell Hammon Evans was the brother of Joseph Hatfield's wife Martha Evans. He and his wife, Phoebe Musick, came to Blackberry Creek with four children, all of them girls. They were Nancy, Anna, Martha and Sarah. Nancy, Anna and Sarah would eventually marry three of the sons of Valentine and Mattie, while Martha would marry Garbriel Rife Jr. Phoebe Musick was the daughter of David and Annie Musick, and thus the stepdaughter of Ephraim Hatfield and step-sister of Joseph and Valentine. When her father, David, was killed by Indians in 1792 and her mother and brothers kidnapped, Phoebe was a newborn.
So there you have it. Three families with 14 children under the age of 11 leave the only home they have ever known and head out into what at that point is still very much the wilderness.