Where are the Dark Menhirs during the Grandmaster Battle?

They're still OHKO touch, right?

Dark Menhirs never 1HK. During the JQ, they always bring your HP down to 100 HP. If your HP is lower than 100 when you get hit, you'll die. You can have 105 HP, get hit by one, and it'll bring your HP down to 100.
I'm ranged, so I don't know if the Dark Menhirs she summons do the same damage, but I know they don't 1HK.
You're thinking about the regular Menhirs in the Valley of Heroes.

Edit- I guessed wrong in thinking italicizing "she summons" would emphasize enough that I know and am saying JQ Dark Menhirs and summoned Dark Menhirs aren't the same. But still answers his question, neither of the Dark Menhirs 1HK.