Here is what I have on Cornelius. I guessed that he was most likely the father of those members of the Rouse family who headed Abbeville District households in 1810 and 1820.
Paul

Cornelius Rouse, born say 1740, was a "Molato" taxable in Bladen County, North Carolina, with (his brother?) John Rouse in 1771 [Byrd, Bladen County Tax Lists, I:61]. He was a "Negroe" head of a Cheraw District, South Carolina household of 2 "other free" males above the age of 16, 2 "other free" males under 16, and 7 "other free" females in 1790 [SC:358], 15 "other free" in Barnwell District in 1800 [SC:62], and 9 in Abbeville District in 1810 [SC:84]. He was called Neale Rous when he received pay for thirty days duty in the militia in 1782 [S.C. Archives Accounts Audited For Revolutionary War Services, AA6636, frame 466, roll #128]. He was granted administration on the Marlboro County, South Carolina estate of John Rous on 8 June 1790 [Minutes 1785-1808, n.p.]. He may have been the Cornelius Ross (born before 1776) who was head of an Abbeville District household of 5 "free colored" in 1820 [SC:5a]. He may have been the father of

i. Edmond Rouce, head of an Abbeville District household of 8 "other free" in 1810 [SC:82].

ii. John2, head of an Abbeville District, South Carolina household of 6 "other free" in 1810 [SC:82].

iii. Charles, born before 1776, head of an Abbeville District household of 6 "free colored" in 1820 [SC:5a].