Character on keyboard deviously tries to put in request (8)
I believe the answer is:
asterisk
'character on keyboard' is the definition.
(symbol on a computer keyboard)
'deviously tries to put in request' is the wordplay.
'deviously' is an anagram indicator (I've seen this in other clues).
'to put in' means one lot of letters goes inside another.
'request' becomes 'ask' (to ask is to request something).
'tries' anagrammed gives 'steri'.
'steri' placed into 'ask' is 'ASTERISK'.
(Other definitions for asterisk that I've seen before include "Sign" , "Star of typography" , "Sarkiest (Anag)" , "Star shaped symbol" , "star-shaped figure" .)