How can I get past the shepherds who block the path

Hint 1 of 5:

They need a demonstration of your power.

Hint 2 of 5:

Perhaps nothing you know yet will affect them.

Hint 3 of 5:

Have you explored the city yet?

Hint 4 of 5:

You need a frightening spell from the crystal ball in the city.

Hint 5 of 5:

Using the TERROR draft will scare them away, so you can pass.