After Vos is turned to the dark side by Dooku, Ventress ultimately manages to redeem him, but she is killed by Dooku with Force lightning shortly after.

How does Ventress die Star Wars?

Ventress reluctantly helped Vos and Dooku in fleeing from Jedi pursuit but refused to embrace the dark side once more. Instead, she sacrificed herself when Dooku attempted to kill Vos with Force lightning by absorbing the blast to protect her lover.

How did Asajj Ventress die in legends?

When Dooku attacked Vos with Force lightning, Ventress shoved Quinlan out of the way and took the brunt of the attack. Vos defeated Dooku, but refused to give into the dark side and strike down the count. Asajj was mortally wounded, and died in Quinlan's arms, grateful that her love had found his way back to the light.