In hippodrome, garlanded last character (5)
I believe the answer is:
omega
'last character' is the definition.
(Greek alphabet)
'in hippodrome garlanded' is the wordplay.
'in' indicates the answer is hidden within the clue.
'OMEGA' is hidden in the letters of 'hippodrome garlanded'.
(Other definitions for omega that I've seen before include "Greek long 'o'" , "Athenian character" , "character in Greek literature?" , "Ultimate letter" , "letter to Greeks" .)