Sebastian 'Seb' Wilkes is an investment banker – Director of the Trading Floor at Shad Sanderson in London. He is an acquaintance of Sherlock Holmes, whom he met at university. He remarks that even at university Sherlock was performing his deduction skills on people. Sebastian appears in "The Blind Banker" where he retains Sherlock to find out how someone managed to break into the Shad Sanderson Bank.