Delenn III was a figure who lived sometime between the 23rd and 28th Centuries who prophesied that the Anla'Shok would help Earth in its "time of greatest need" - the devastation following the Great Burn. Her words were still remembered by 3262, a time in which Earth remained in a pre-technological state, and her prophesies became the subject of holy texts maintained by the church.
Based on her name, she was likely a descendant of Delenn and John Sheridan by way of their son David Sheridan II. Her name also implies the existence of another ancestor named Delenn (Delenn II) living at some point between herself and David. Being a descendant of Delenn and John Sheridan would also make her a human-Minbari hybrid and a descendant of Valen as well as 19th-Century US Army Gen. Philip Sheridan.