Argyle King
Legend
There is no such thing as actual invisibility in the real world though. No living thing is actually invisible in the entire span of the world.
Nothing in 5e was ever absurd to this degree. Once you take this out of the realm of a player acting up and dancing in front of guards, and turn it into "players immolated by a dragon that "hid" in a bush 600 years ago and has been flying around invisible ever since" or "An army of hobgoblins hid behind a hill once, now they march invisible past every single town to sack the capital directly" then it is clear that this interpretation of the intent is nonsense.
There are prototypes for invisibility cloaks that function by manipulation of light.
Infrared light is normally not visible, but there are real-world methods for being able to observe that it is there.
Even ignoring that, camouflage and invisibility are defined differently in relation to how human vision typically works.
Do I think that the current interpretation of how stealth and invisibility works in D&D 5e24 is nonsense? Yes, and I have said that.
However, with the limited information currently available to be, it appears that the 5e24 rules currently offer no way to interpret how it works without creating broken interactions with other aspects of the game.
Another example of something absurd could be that the entire army you've mentioned could grapple a character, and the character would still be able to use a longbow.
In 3rd Edition, a high level fighter with the right chain of Cleave feats could teleport around the world in 6 seconds by lining up a bunch of commoners and killing them.
In early 4th Edition, I could use Mirror Sphere to force a character to eat itself.
5th Edition isn't immune to having some unusual rules.
It's not difficult to houserule that a "hidden" condition exists in 5e. However, such a thing does not currently appear in the 5e24 rules.