When 'teller is killed in own story', it can be a very powerful literary device. It can be used to show the unpredictability of life or the story's world. It can also create a sense of irony. For instance, if a character is telling a heroic tale about themselves but in the end, due to their own hubris or some unforeseen circumstances in the story, they are killed. This not only surprises the reader but also makes them reflect on the character's journey and the nature of the story itself.