It's a fantasy role-playing game.

DM: You are Vex Vex'ahlia, a half-elf ranger . You are the member of the famous group of adventurers. Previously, At the Platinum Sanctuary, the twins are greeted by Highbearer Vord. He offers to seal Opash's book in a vault beneath the city, but Vax, who doesn't entirely trust him, tells him they didn't actually bring it with them.
DM: Puts his hands aside and steps back. "Oh. Well. Return with the tome, should you see fit to leave it here."
Player: Can I ask you, how much do you know of Orcus?
DM: "I know enough."
Player: I don't know much of anything, and it's important that we learn.
DM: "Hmm." So, he nods to one of the other advisors who steps off for a moment. "Sit a moment. This is a conversation to have." And some of the guards come and bring a few chairs and set them behind you. "Orcus, the demon prince of undeath, resides in the depths of Thanatos, one of the varying realms of the Abyss. It is here that he snuffs the life from all creatures and brings them under his sway. He is an entity of ever-hungering need for power, and to take all life and break it so he can bring it under his control. Thankfully, as one of the betrayer gods, he was sealed away, and the Divine Gate was placed up to prevent his, and any other evil entities' entrance into our world. However, that does not prevent him from sending his minions, sending his powers, sending his influence out through the permeable, small gaps in this gate. So his influence remains."
Player: He only has two horns, right?
DM: "Oh! Four, once."
Player: Four?
DM: "Two that he maintains on himself to this day, and two that were severed, enchanted, and bequeathed into two of his, at the time, one of his champions."
