In the world of my book, "Legend of the Dreamseers", dreams and nightmares are sentient beings. They are invisible to most humans, but there are some born every few hundred years who can interact with them. Dreams and nightmares can enter someone's mind and give them a vision. These visions vary wildly in type, depending on whether the dream or nightmare is trying to give a message, influence someone's memories, or simply do a good or evil deed. Dreamseers (people who can interact with dreams) have different levels of power, from Watchers, who can only see dreams, to Keepers (who can communicate) and Riders (who can physically interact with dreams). Certain other creatures can interact with dreams to different extents, and one or two even prey on them. Some dreams are more powerful than others, and the most powerful can even indwell the mind of a human.

That is very interesting! Are you kind of basing this off the idea that there are 'unseen forces all around us'? And are dreams and nightmares messengers for a higher power?

That's really fascinating. Do dreams/seers serve good, and one serve evil? Or is their fate their own choice?

As for where I got the idea, I just thought that it would be crazy if dreams were not from our own minds, but from an outside influence. The idea developed from there. Yes, dreams and nightmares are often messengers, some used by humans, others in the service of God (or the enemy). Dreams and nightmares are really one race, but they are classified separately according to whether they choose to serve good or evil.

That's an awesome idea!
So do dreams choose who they serve, or are they forced to serve?

Alright, here are the answers to your questions:
Dreams and nightmares are the same species, they're just classified separately based on whom they serve. And yes, they get to choose. Dreams exist on another plane of reality, and those with the gift of Dreamseeing (including some animals) are able to interact with that plane on varying levels depending on their power. The most powerful can interact physically with dreams. For normal humans, however, dreams are an invisible, intangible presence.

They sort of sound like the dream people in Lois Lowry's Gossamer! Interesting!

Can they take a physical shape where everyone can see them, or are they limited to only the dreamseers being able to see them?

Hmm... I've never read Gossamer. Now I'm torn between reading it now and risking looking like a copycat or waiting till I finish the book. And Griffin, dreams can only be seen by dreamseers. It's because they aren't entirely in our plane of existence.

What do they look like? Can they change depending on what kind of Dream they are, or do they have a fixed appearance?

They have a general sameness of appearance, but like different breeds of dogs have different features so do different types of dreams. Each one is unique, and they can't take different forms, they're stuck with one. At least, that's how it is for now... I might change that if the story requires it.

Hey, to anyone who stumbles on this post, I started a new thread about these guys in Peoples, Race, and Tribes because they're not really animals anymore...