This article analyses the main empirical and clinical substrates of the concept of death pulsion by carefully reading the first text in which the concept is formulated and the second main text in which it is present, respectively, in addition to the principle of time and O Ego and Id. It has been assumed that death pulsion is introduced into freudian metapsicology with a strong call for biological arguments and is more consistent from 1923 onwards, with the concepts of de-fusion, aggression, feeling of guilt and supgrim. The feeling of guilt appears as a key key to reading O Ego and Id in linking aggression to the pulsion of death as a consistent substrate of the concept. Finally, the article highlights how the pulsion of death is more easily linked to the clinical dimension from then on.