So what exactly are the dream guardians? (spoilers)

[Muado 93]

In the end, when fighting The Emperor he ends up summoning a bunch of dream guardians. Then one of my companions says to one of them "I know you from my dream!"

I thought he was the dream guardian! So are they separate beings or different manifestations of him as he entered each of my companion's dreams?

And if they are seperate beings....then where the hell is my big booty, high-elf waifu?