Selûne is the FR goddess of the moon, and is quite an important figure in the setting’s pantheon. She originally created the world alongside her sister Shar, the goddess of darkness. Together they also witnessed the “fissure of reality” that split that world in two, Abeir and Toril. That fissure is the reason why the Realms were Forgotten.

Shar is responsible for a lot of evil shit throughout FR’s metaplot, including the events that happened during the Spellplague/edition transition to swap bits of Abeir’s and Toril’s geography around.

Selûne used to be a goddess who took the path of forgiveness, compassion and self-sacrifice, but the last century has seen her become more aggressive and proactive in battling evil. Light must battle darkness if it is to prevail.

The book doesn’t suggest using her domain for priests of any other FR god. I don’t think any of them are moon-themed enough.

Mechanics

Warpriests of Selûne benefit from having a high Constitution, since a lot of their power riders use the bonus for that attribute. These riders usually focus on granting allies damage resistance or bonus damage, and in penalizing enemy damage or attack rolls.

Her signature damage type is “cold and radiant”, which means PCs can potentially benefit from two of the edition’s most infamous feat combos (Permafrost and Radiant Mafia). That’s the domain’s greatest feature according to the optimization forums. It helps that their Channel Divinity power makes enemies vulnerable to radiant damage.

Lots of radiant damage makes this domain powerful against undead, which is true for most others. Its Level 1 Utility is a daily that makes the warpriest’s weapon count as silvered for the entire encounter, also making it a good counter to lycanthropes. As we saw on the character themes, there are quite a few of those among the possible foes in the Neverwinter campaign.

Impressions

You would think this would be an appropriate domain for clerics of Sehanine in the core setting, but I think this version of Selûne is a bit more aggressive and militant than the trickster-ish Sehanine Moonbow. Corellon’s domain would fit her better.

You could say this is the domain for priests who worship Sehanine’s wrathful face, perhaps. And it’s a good pick for any player who wants their central concept to be “fighting evil by moonlight”.