Got a question about Green Lanterns wall clix fx thingy So this came up. If the wall is placed on top of elevated terrain do people around the base of the elevated terrain on the ground get the minus one?

By the "base" of the elevated, you mean the Light Wall is on level 2 and the characters are on level 1 next to the wall's square? If so, then no, an opposing character's defense would not be modified, because they wouldn't be adjacent to the marker, as they are on different elevations.

Yes this is what I meant (and what I figured was right). Thank you.

Interesting [C]

[C]If a wall shares an edge with two different levels of elevation, that wall exists on the both levels of elevation. If that wall is destroyed, place a debris marker on each side of the destroyed wall, regardless of elevation.

Since the light wall is a wall, I think this would affect characters on both elevations.

Velcade is correct.

A Light Wall marker is considered a Wall for all game effects.

http://win.wizkids.com/bb/viewtopic.php?f=3&t=11925

As long as the wall was oriented so as to share that edge, yes.

If the wall was turned so as to not share an edge with the lower elevation then the characters on that lower elevation would not be adjacent.