Williams arrives from Indian Premier League side Kerala Blasters having spent much of his career at Scunthorpe United before his move to India.
The 30-year-old left-back also names Reading, Peterborough United and Sheffield United amongst his former clubs.
Goalkeeper Deasy (pictured) joins the club from Altrincham where he made forty-one appearances last season.
The 30-year-old has also featured for Gateshead, Barrow AFC, Stockport County, Macclesfield Town, Bradford Park Avenue and Northwich Victoria.