At first it seems a great irony that the Count of Monte Cristo should meet and save the life of Albert de Morcerf during the Carnival, yet later in the narrative the reader learns that such happenings have been designed by Monte Cristo.  For, in gratitude, Albert invites the count to his home.  And, while Edmund Dantes knows that Albert's father is his mortal enemy of old, Ferdinand, the cousin of his beloved Mercedes, he does not realize who is the mother of Albert. In Chapter 42 Albert escorts his guest to his elegant bedchamber where  

a single portrait, signed Leopold Robert, shone in its carved and gilded frame.  The portrait attracted the Count of Monte Cristo's attention, for he made three rapid steps in the chamber, and stopped suddenly before it.  It was the prtrait of a young woman...The light was so faint in the room, that Albert did not perceive the paleness that spread itself over the count's visage, or the nervous heaving of his chest and shoulders.

Now, the true irony occurs, as Monte Cristo recognizes the beautiful Catalan woman as Mercedes, his only love, now the wife of his enemy and mother of the son he would destroy as a tool of vengeance.

Ferdinand, now the Count de Morcerf, is the most decorated soldier in France.  He has won many battles and conquered kings of foreign Eastern lands.  However, his glorious past is sullied, and Monte Cristo will be instrumental is effecting de Morcerf's demise.