There is a way to do this without increasing server overhead.  When you receive the message that tells you whom you've killed, the server presumably sends a string literal (a series of characters) to your front-end (a very low-cost operation).  These string literals can then be saved to a larger variable or .txt file on the user's front end.  When the user lands, then the front-end queries the .txt file for the information, which the front end displays independent of the server.  That's the most barebones way to do it.  One could add a full GUI, encryption, a rich-text or spreadsheet format; the possibilities are endless.
-Penguin