Gentleman and the Witch by Eve Langlais

He promised her immortality, but first she must survive a dangerous quest.

Becoming a witch at sixteen started me on my path to greatness. A little hex here. A little spell there. My foes never knew what hit them. That magic became lucrative later on when I started my own business, but surely I am destined to do more than make skincare products for those trying to hold on to their youth.
When a gentleman who claims he used to be a god demands my help, I laugh him off. As if I’m going to put myself in harm’s way for him. However, when my home is destroyed, I decide to join him on his quest for revenge. After all, it turns out we have a common enemy.
What I didn’t expect? To end up fighting for my life on another world. Nor did I think I’d fall in love.
An affair short-lived.
Evildoers might want to use me to advance their cause, but they might end up surprised because I’m not a good witch. I will do anything, even end the world, to avenge those I love.