Henadic Theologian
Legend
I'd be happy to help on that, I know lots about them and can offer the original lore if your friend's not interested in the new lore.
They're a great faction because their entire ideology is based on a mistranslated prophecy their leader refused to admit he got wrong. He didn't even make that big a mistake, but moving the period one word over changed the entire meaning of it.
The Cult's had lots of schisms and internal power struggles and oftentimes deceives new members, so it's easy to justify even a Good PC having been a member before the start of the campaign.
Sammaster's faction of the Cult of the Dragon & Tiamat's Faction are not the only Factions.
Ashardalon has his own faction of the cult of the Dragon in the new Fallbacks novel [Spoiler/]