There was a Ludwig Fulk (by any several spellings) who was killed in the massacre at the fort at Upper Tract as was his wife in what is now Pendleton Co. (then Augusta Co.) in 1758.
It's possible - maybe likely - that he was aka Ludwig Falck who arrived on the Ship Sally on 17 Oct 1750. He is probably the same Johann Ludewig Falk who was married later that year to Anna Christina Schuler in Philadelphia.
Frederick Maus (mis-transcribed in the recording in Pennsylvania German Church Records as Maut)was a witness to his marriage. The same Frederick Maus was the brother of George Maus (aka Mouse) was also the victim of a massacre at Seybert's fort the day following the massacre at Upper Tract. (There is additional evidence of a familial relationship between the Maus, Schuler, and Falck families in the records of St. Michaelis and Zion Lutheran Church of Philadelphia).
I don't postulate a relationship between David and Ludwig but mention it only as a possible lead.