Ranger's are often overlooked. It is a class that doesn't feel like it has much place when you have alternatives that seem to do the same things just as good or better. But it has something that other classes don't have as much of (and it isn't animal companions). Rangers have flavor. Their class and archetype features tend to be just as aesthetic as they are functional.
This subclass was written with flavor in mind. And it was modeled after a famous fictional character that you might not expect to fit into a ranger archetype: John Constantine.
The hell skulker is a ranger that has survived hell and is consequently prepared to take on pretty much anything else. With some minor overlap with cleric-like abilities the hell skulker can resist powerful charms, summon a demon contractor, bargain with greater fiends, and unleash the powerful magic of the hells and abyss when in a pinch.
- from the publisher's blurb