It's ironic that the Pardoner tells such a tale of greed, because he himself is greedy. By using irony in the Pardoner's Tale, Chaucer is criticizing the church system. Like many Pardoners of his time, the Pardoner would accept money in exchange for forgiveness of sins but instead of using the money for church charity, he used it for his own satisfaction.
Three men were told they could find Death under a tree upon a hill but when they got there, they found money instead. Since they found the gold they all thought that they were not looking for Death anymore but in reality they really are, they just do not know it.
Another ironic thing about this story is that the three men were going to go "kill Death". You can not kill Death because Death is not living. You can not kill something that is already dead. Chaucer is personifying Death in this story.
The Pardoner's Tale is such an ironic tale because, he is greedy and stole money from the church by keeping it, but he talks about how people should not be greedy and should do the right things. To deceive mankind is the Pardoner's business. He takes money from people to pardon their sins, but keeps the money for himself, yet his story gives the moral of, "be a good person".
