Sir Bernard Selachii is probably the most illustrious Assassin of the noble house of Selachii, who have been alumni of the College of Assassins and, often, practising Assassins for many generations.
Famed at the Assassins' Guild school for the sheer presence of mind he displayed in a situation where, with no defensive weaponry to hand, he was cornered by an assassin financed by a business rival. Selachii spent the entire evening with him, reminiscing about the great days they had shared in Wigblock House, before suggesting that they drink a toast to the Old School. While his would-be assassin held his glass aloft, however, Sir Bernard beat him to death with the brandy bottle.
Subsequently, Sir Bernard endowed the Sir Bernard Selachii Award for Sheer Coolth, a much coveted prize to this day.
The story is related in the The New Discworld Companion and the Discworld's Assassins' Guild Yearbook and Diary 2000.