No, reject Mandy

Much as you were tempted, the reality was that this being an eldritch predator from another dimension. She was a creature with an entirely alien morality that you couldn’t rely on to be comparable with your own. What if she betrayed you? And what sort of horrors would she unleash once the cult was defeated? You’d be trading one evil for another. You couldn’t risk it.

“I’m sorry, but no.”

Mandy’s dark eyes narrowed to slits and the air grew several degrees colder. “You’d reject me? You’d spit in my face after I offered you the chance of a lifetime?”

You braced yourself for some kind of blow, but it never came. The wind picked up and the fog grew dense, but when you blinked Mandy was gone. Her voices whispered in your ear, fading fast, “You’ll regret this. The next time we meet, I’ll cut you down like the others…”

It passed by, and you were alone on the bridge. It would be a long walk home.