Who is Edward d'Eath from Men at Arms: A Novel of Discworld and what is their importance?

Edward d'Eath is an assassin. He belongs to the Assassin's Guild of Ankh-Morpork, and he is also the heir of a rich and wealthy noble family. Living on the edger of madness, Edward d'Eath is preoccupied with the 'glory days' of Ankh-Morpork; namely when there was a king, and knights, and wealthy noble families. He serves as a symbol of the stagnant views of the past, and is a living obstacle to the Modernity that 'men At Arms' concerns itself with.