De-Picted

Question: I know there is even less information on the Picts than there is on the Gauls, but I just want to know two things. Did they worship two deities called the Forest Lord and the Man in the Moon, and did they make human sacrifices to these gods?

I hate to tell you this, but the answer is probably not. There's a great deal of literature out there, both on the internet and off, purporting to tell you about the ancient religion of the Picts, but those materials are mostly lying to you.

The fact of the matter is that we have literally no idea whatsoever what the Picts believed; they left no written record, no artistic or archaeological record that we can reliably tie to a religion, and never had anything written about them by other cultures except that they were "pagans", which just means non-Christian. Most scholars assume that they probably followed some flavor of the Celtic polytheism that was popular around that time and area. As far as we can tell, they probably followed the same general religious practices as other Celts in the area at that time, though we don't know anything for sure.

For Scion's purposes, that means the Picts were most likely followers of some brand of the Tuatha, with perhaps a little Nemetondevos thrown in for seasoning. If you wanted to get meta with it, you could consider the mostly-extinct Pictish "pantheon" to be made up of those pesky Celtic gods that defy categorization - the Croms and Cailleachs of the islands. It would be an interpretation rather than a scholarly certainty, but if you're bent on using the Picts, it's as good an approach as any.

The Forest Lord and Man in the Moon, unfortunately, sound like made-up modern mumbo-jumbo to me. Some modern Wiccan and polytheistic faiths like to refer to a generic Forest Lord as a major deity, but they're usually distilling a bunch of historical gods down into one figure without regard for where they came from or what they represent; Cernunnos and gods like him are especially popular for this sort of thing. The closest Man in the Moon figure I know of is the distant Titan Mani of Norse mythology, and there's no evidence whatsoever of Pictish worship of any such deity.

We similarly lack specific records of the Picts that discuss human sacrifice, but the other Celtic tribes that they might have shared religious belief with sometimes did, particularly the cults of the Croms and the Nemetondevos. It would probably be likely that they did so if they worshiped similar ancient gods; if you decide to run them more aligned with the Tuatha than the older gods, they probably did so much less, as that pantheon is one of the most sacrifice-light in the world.