From: Inhumans vs. X-Men #3
Seeing the Inhumans under attack by the NYPD, Bruce Banner transforms into the Incredible Hulk in order to lend a hand. The Inhumans seeing The Hulk as their opportunity to show the world that they are not a threat attempt to subdue the jade giant and “save” the city. They get more than they bargain for when The Hulk proves to be an almost unstoppable force.
Karnak, the one who finds the fault in all things, probes ol’ jade jaws and finds that his weakness is his chest, right over his heart and attempts to exploit this weakness.
The results were disastrous….
From: The Inhumans #12 (1977)
Karnak has the extrasensory ability to sense a weak point in any object or person around him. By applying pressure or hitting the weak points, he can down enemies stronger than him, or break seemingly invincible objects. Because of his discipline with martial arts, this sense is effortless and can use it for periods of time.
Karnak is also a master martial artist who has developed callouses on his hands, allowing him to shatter wood and exchange blows with superhuman opponents who greatly outclass him in durability and strength.
Unlike most Inhumans, he does not have superhuman powers as a result of exposure to the mutagenic Terrigen Mist, as he was never exposed to the Mist. Instead, Karnak has the extrasensory ability (achieved through meditation and intensive training) to perceive stress points, fracture planes, or weaknesses in objects or persons. He has complete voluntary control of most of his autonomic bodily functions. All striking surfaces of his body are extremely toughened. He is capable of shattering substances up to and including mild steel and rendering superhuman opponents unconscious by striking them.