We played a game the other day and I placed KC GL 6 squares away from my starting area. My opponent went first and tk'd his Supes out who then immediately KO'd KC GL. My question is, was he OK to do this or does first turn immunity apply ?

The figure does not state it is immune to first round immunity. So no he cannot attack you.

Turn 1, unless the KC takes an Action OF ANY SORT the figure cannot be attacked/damaged/etc.

It's an interesting question, the first-round immunity allows for characters who have been placed to be attacked during the first round and the kc figs wording does say they are placed 6 squares away from the starting area at the start of the game.

I think the answer is in the wording of what happens when you put the rest of your figures on the map, are they placed or does it say something else?

He begins the game placed at least 6 squares from a starting area.

This is no different than all the other characters on your team. They are also placed before the game begins.

Step 3 of Preparing for battle (rulebook page 5)
First Round immunity only cares about what happens during the first round.

First Round Immunity (Rulebook page 7)
So if first round immunity don't apply to that Green Lantern then it does not apply to any character.

The opponent went first.

This KO should not have happened.

OK. Thanks for the replies! I think answers my question!