Basicly in book's ( Orginal Witcher saga by Sapkowski) Geralt is destined to death .. she walks with him. Sword of destiny got two edges one is Geralt another one is death.
Geralt is quite similar to Darksiders' Death. Dry humour, Sarcasm, Cynicism, Sassy, Introverted, And both have reliable steeds such as Roach and Despair