Personally, I'd get one to say Tim Curry's lines from Legend.
"Was it not your sin trapped the Unicorn, even now, the evil seed of what you have done, germinates within you."

Can you actually keep ravens as pets, or is it only under certain conditions?

I think you need a lot of permits to keep one. They're considered "wild" and "exotic" animals so you'd have to sink a LOT of money into providing proper care & facilities.

Of course, that's in the US. Other countries may vary.

You could always get a black mynah bird. They're much smaller than crows, but excellent mimics. They still require a lot of time, attention & care but are probably a lot easier than ravens or other corvids.

Crows are sentient individuals that live in nature, just go befriend one. Bring snacks, sentient things like snacks.