You assume he's not fibbing. The 5 new acquaintances vary from what looks like 3 normal women, to a heavily clothed figure who obviously is not, to a native who could go either way,
"Everyone come here. I need to explain things to all of you, as some of you know various bits of what's happening, but none of you knows everything. I'll begin with some hard truths. Think of Life, the universe, and everything as you know it as a page in a book. The other pages of this book are other worlds and places. The art will allow you to travel to them, but I don't recommend trying it until you are powerful enough to have left mortality behind. There used to be powerful beings, known by many names, which you have heard me refer to as The Enemy. They are powerful enough in relation to us that they could be considered Gods, and they exist simultaneously on every page of the book. Or at least they used to. There are beings more powerful yet, and they do not like being challenged by power hungry young upstarts. They banished The Enemy to the spaces in between the books pages, imprisoning them there for some time. Not forever, as that is not possible, but long enough that it would seem so to us."
"The Enemy left it's cults behind though, and these cults can travel from page to page in some worlds. They can spread the knowledge of the Art to developing Species who do not have the Wisdom to use it properly. These useful idiots open doors that allow allies of The Enemy in, which allow them to open larger doors yet. Which allows for more powerful allies to be let through. It creates a self reinforcing loop. Whilst bound to a local town for a time, I noticed one of these allies. An invisible creature that was the size of a house that began threatening the smaller local communities. I have encountered it's like before. It is a Child of the Enemy and a mortal being. A demigod. It is here to pave the way for it's creator by changing this world to one they will find comfortable. Our goal is to bind it, and send it back Outside. We are not likely powerful enough to kill it, depending on how developed it is. Left unchecked, it will spread the Art through tainted lessons that give people the illusion of power,while also corrupting them in ways that make them more like The Enemy than their native species. They will alter both society and the physical world in ways that make the world more like those controlled by their Masters. Most of the worlds population will die, and reality will become something else. Not quickly mind you. It will take it generations. But it has time, and it is as weak now as it will ever be. If we manage to survive this, we must hung down it's mortal parent so as to ensure that this does not happen again. I know this leaves a lot of questions unanswered, but we are pressed for time. We must complete the circle before it arrives, so if you must ask anything, do it as you work."
