Quick p wave question..... If There's 2 characters on elevated terrain and 1 on clear grounded terrain with half the characters range can one of the characters on elevated terrain use pulse wave at full damage assuming both characters are opposing to one another. Because the elevated blocks lines of fire?

It's hard to tell exactly what position you're describing the characters in, so I'll answer in a general manner:

When using Pulse Wave, first halve the character's range value and attempt to draw lines of fire to all characters within that range in every direction.
Then, check to see how many characters you were able to draw range to. If only 1, you use your full damage value. If more than 1, your damage value is locked at 1.

If I'm on the edge of elevated and I can draw line of fire to a character on grounded Terrain would that character be a legal target or no because if you read pulse wave it says elevated terrain impedes line of fire...

"only blocked by wall, blocking, and elevated terrain" means that the line of fire will be blocked by those things as normal. It doesn't mean that they block line of fire if they wouldn't normally.

Maybe draw a little diagram, just to make it clear.

[_][R][_]
[_][L][_]
[_][_][_]
[_][D][_]

The sections in red are elevated. L is Loki, R is Ronan, and D is Doombot.

Loki uses Pulse Wave. You cut his range in half, then draw all possible lines of fire (just the same way you would for making a ranged attack). You could target Doombot, so he's included in the pulse.

Remember, though a Pulse Wave in your mind may look like this

It actually plays like this