supersessor

Etymology
From the participle stem of.

Noun

 * 1) Someone or something that supersedes another.
 * 2) * 1808–10,, Memoirs of a Georgian Rake, Folio Society 1995, p. 401:
 * Lord Wellesley sent down all his carriages, servants, staff officers, and general establishment to receive his noble supercessor at the waterside.