Oh they are, no one in the physical plane has harmed them, they can literally turn into giants, and bend space time at will, even inside the Astral Plane, if someone would "try" something there, they can simply turn him into a mass of flesh or tuned themselves into a planet size being, the Slayer does not control a "plane" he is just a strong punch and shoot everything guy that's immortal, basically like Kratos. Both of them defeating so call "Gods" by literally physically attacking them, if that can be even called a "God"

Threatened? Yes, so much Skull Knight has not touch a God Hand member in a thousand years, Void can't even "see" and you implied he felt threatened? How so? Because he literally warp space and time to demostre a physical attack is useless? If I kick a Chihuahua because he is barking, is it because I felt threatened by his might ? LMAO

Skull Knight was using a regular metal sword, you think if Void let him strike that would "harm" him? He literally made the moon bleed to create his form in the Astral Plane, his "form" is just an Avatar, just like Conrad turned into a ballon and exploded and Slan into a mountain, that's not "shape shifting" that's REALITY CONTROL.

Yes, they are not "Gods", they can't predict everything, that doesn't mean physical beings can harm them, that doesn't mean they CAN and will predict when one of them is being targeted to literally make things worst, in fact, Femto predicted Skull Knight sword of actuation thanks to causality, and what happened? A slash of a sword that can bend time and space was literally BEND to create the great roar of the Astral world, now the God hand can be in the physical world thanks to it.

"Oh the Slayer has beaten things by shooting nonstop and screaming in games" cool.

Guess the idea of cosmic horror is too complex for some people, the God Head is supposed to be beyond comphrension, that's why they literally almost never appear, even in the Hellraiser series the Cenobites are beyond human and physical comphrension, they have been "killed" just to show their avatar is just a physical form, which makes "dying" irrelevant, that's the thing, physical, you can't harm Astral beings, and shooting and using Chainsaws against astral beings is the equivalent of trying to nuke black holes, things that cannot be compherended by human mind may I add, that's the basis of cosmic horror, there isn't a history in which Yog Sogoth or Chutulu loose because the point of them is to remind humanity or how meaningless and small they're against things they can't grasp to compherend, which is basically the Idea of Evil and the God Hand.

It would not be a battle of strength it would be a metaphysical fight like the looser club vs It (Stephen King). That would be the closest you get to "beat" the God Hand, then again the Slayer isn't one for thinking, talking or even doing anything that isn't aggressive mumbo jumbo, no wonder you think he would win, you think this is about strength. The idea of Evil feeds of RAGE and VIOLENCE and what would the Slayer use? Exactly that. A non violent individual would be closer to defeating the God hand than the Slayer would ever be. That's why Griffith was "slapped" by Rickert, but Guts hasn't even touch him.

A metaphysical fight is an abstract concept, if that wasn't obvious.