Character:

Undertaker is, as his name suggests, a funeral director. He often works with corpses resulting from movements in the underworld of the United Kingdom and acts as Ciel's informant. He seems to have known Ciel's father, Vincent, as he appears as one of the "Evil Nobles". He is a rather eccentric man, almost always wearing a smile, and wishes to hear a funny joke for his services instead of receiving any of the "Queen's money". He shows a strong disdain for the Queen. In the anime adaptation, he is a legendary and retired Shinigami ranked in the Management level and is highly respected by William Spears. Although he is retired, he still can access the Shinigami Library and alter the books, which he often does not return.

Source from Wikipeida