Ishmael is a firm woman. She once was an office worker, then a sailor, then something something giant whale killed wife and now vengeance creed. I don't entirely remember her Canto. However, she is a woman driven to achieve her goals no matter the cost.  

Ishmael's voice is medium pitch with a very firm tone. She's not overly complicated; she's astute in her words and enunciates each word as if to accurately convey her message. While her tone is soft, it carries the unwavering certainty in her resolve. 

Ishmael's voicelines/reference can be found here.