Shirogane Mushi

From Kokorodatabase

The Bard's Tale (aka, "insert pretty music here")

Long ago...

There was a time when dreams became reality, and new dreams were born.

It was a golden age for mankind-- a paradise on earth. However, dark desires also manifested themselves...

The Nightmares, born from the evil within people's minds, shook heaven and earth. Those who opposed it were turned to ashes.

The world was on the brink of destruction.

"At this rate, the world will surely come to an end. There is only one way..."

Determined to save humanity from evil, a sage stepped forth, with his brave companion alongside him.

By seperating the tainted dream from the real world, the sage weaked the Nightmare's overwhelming power.

A fierce battle ensued, lasting seven nights and seven days...

And finally, by the power of the Holy Instruments and the Dream Stone, the Nightmare was sealed in the holy land.

The darkness which engulfed the world lifted, and peace was restored. But the world was now divided in two-- dream and reality

Mushi

Mushi is a Dreamworld Mew, although not in the way you think she is. Rather, due to what her DNA entails, along with a few other kinks here and there, the poor girl has the ability to enter people's dreams. This may sound fun, but then you stop and realize that she can not only interact with what's in the dream, but can be hurt by monsters and other hostile forces, too.

Yeah, so it's not anyone's idea of a dream job, no pun intended. But someone has to do it, and Mush was apparently compatible with the DNA, or otherwise there'd be no story