quake reads:

Giant reach reads:
So if a char uses quake and has giant reach, can he target characters with giant reach or is it still limited to attacking adjacent characters? Not sure which supersedes which

Any help will be greatly appreciated!

Yes, the Giant Reach text explains it:

OsArkady has this correct.

Giant Reach: X would basically just change Quake's text to say:

"When this character makes a close attack, they may use [Improved Targeting: Hindering] and target all opposing character(s) within X squares and line of fire. If they do, they gain KNOCKBACK (for this attack) and deal each hit character 2 damage instead of normal damage."

Thanks for providing the answer to this question , OsArkady . It's a tremendous help for a team I'm planning to field .

The more giant your reach, the bigger your Quake, yep. A classic giant-size maneuver.