Blofeld is head of the global criminal organisation SPECTRE and is commonly referred to by the codename Number 1 within this organisation. The character was originally written by Fleming as a physically massive and powerfully built man, standing around 6 ft 3 in and weighing 20 st, who had become flabby with a huge belly.

The most recurring antagonist in the franchise, Blofeld appears or is heard in three novels: Thunderball