In "The Pardoner's Tale," Death is personified as a killer and a thief. When three young scoundrels who are hanging around in a tavern, drinking, gambling, and swearing, hear that their friend has been killed by Death, they immediately set out for revenge.
Once they leave the tavern, the three young men come across an old man. They immediately question him as to Death's whereabouts. The old man replies that he asked Death to take him, but Death did not oblige. However, he is able to tell the three friends that Death is to be found at the foot of an oak tree.
When the men find the tree, they discover a horde of gold coins. Greed immediately takes over their souls, and they completely forget about their plan to kill Death. The men decide that they will sleep underneath the tree overnight and then take the gold coins with them in the morning. As no man can trust the others, they decide to draw lots to determine who will go for food and drink while the others stay behind to guard the gold.
The youngest of the men draws the short straw and goes off to fetch food and drink. He plans to poison the others' wine and steal all the gold. In the meantime, his friends have their own murderous plan in mind; they're going to overpower and kill the young man when he returns and divide his share of the gold coins among themselves.
Sure enough, when the young man returns with his food and drink, he is overpowered and killed by the other two. They celebrate their good fortune by drinking the poisoned wine, which of course kills them.
Some scholars have held that the old man is a representation of Death. But the scholarly consensus is that he is, at best, merely a messenger of Death. He was, after all, the one who told the three greedy young men where Death was to be found: underneath the oak tree. And he was absolutely right, too, because that's precisely where all three met their deaths due to their insatiable greed.