How does one Kill death Itself?

The Cryshos Heirs have to kill their counterparts to gain their strength and be Emanator level beings if they weren't already, but i wonder, since they have to kill their God Counterpart, how Would Castorice Kill Death itself? It would be so interesting to watch...she said That Thanatos separated her from her other half. Most likely the dragon. They are based on the zodiac sign Gemini and Their names are Castorice and Pollux, a direct reference. In Irl lore Pollux is Immortal and shares his immortally with Castorice so that's interesting...