In addition, the technology is expensive and dangerous for normal humans to use.

Even though you can get into places normal humans can't?

By the early 19th century their contact with 'normal' humans had diminished.

He ages at a much slower rate than normal humans.

Others look like normal humans, only with a bit different facial features.

At this pressure, that was just barely enough to keep normal humans going.

The face behind the mask, the place where normal humans couldn't go.

A few, it is said, are not even aware of their true nature and consider themselves normal humans.

They'd have hidden their tracks in places normal humans wouldn't even think to look.

For us normal humans, the future is not a place to meddle with.