God of Shadows and Blood, very interesting and he should have an interesting death. When stuck on things like this, I always try and think of key words related to the character. Maybe something related to this. 

Shadows, maybe a death related to: secrecy, deceit, betrayal, or thievery?

Blood: which could be related to poison, love, lust, rage?

Edit Just read he had a hard time with love, why is that? Maybe his death could be related to a new love, or an old one. Jealousy of another man as his woman has fallen for him?