Death is efficient but not cruel, and sees his job as a necessary public service. His task is not to kill, but to collect. He harvests the old, worn-out souls of the dead. His is a necessary service as life force that isn't properly removed from the Disc tends to produce unusual behaviors and phenomena. Death is intrigued by humans and their cultures, and attempts to imitate their lives by adopting a daughter and building a house; however, without the emotions and biological needs which motivate humans, he is unable truly to understand why humans do the things that they do and his imitative actions often have fundamental flaws.
Death is not invisible; however, most people's brains refuse to acknowledge him for who he is, unless he insists. Under normal circumstances, only those of a magical disposition (e.g. witches and wizards), children, and cats can see him, or allow themselves to see him. Due to his eternal nature, Death can ignore such things as walls or magic spells; he exists through all time, and therefore things lasting merely centuries are not as real as he is. He can only go where people believe in death and can only see people who can die.
He is fond of cats, who can see him at all times, and curry, which he says is like biting a red-hot ice cube.