Last character incorporated metal (4)
I believe the answer is:
zinc
'metal' is the definition.
(zinc is a metal)
'last character incorporated' is the wordplay.
'last character' becomes 'Z'.
'incorporated' becomes 'inc'.
'z'+'inc'='ZINC'
(Other definitions for zinc that I've seen before include "Blusish-white lustrous metallic element" , "Bluish-white metal" , "Ingredient in brass" , "Metal much used in alloys" , "White metallic element used in alloys" .)