There is a concept that our world mirrors the spiritual worlds. Shiurei Daas speaks of this at length.
Based on that we can can give the following explanation. Before man sinned, the man's relationship with G-d was based on a paradigm of Hashem giving and man obeying his will. After the sin, the paradigm shifted to Hashem giving to a rebellious being.
I am providing a source for the answer but one will need further research to better understand it.
Gemorah avodah zara 3b states that "He (the Almighty) sits and makes sport with the leviathan"
So at least we know that the male leviathan is not dead as opposed to his female counterpart.