I like the idea that the translation sounds kind of cryptic and mysterious, so I personally wouldn’t want to make the instructions too explicit. (“Yo! If you’re evil enough, we’ll give you the location!”) I think my two favorites of Hal’s are:

The Sith fortress on Exegol is hidden from the light. Surrender to the darkness within to find the way. To the wielder’s dark nature, only this blade tells.

and

The Sith fortress on Exegol is hidden from the light. The Wayfinders reveal the path to acolytes of the dark. To those it chooses, only this blade tells.

Tweaked a little further, it could possibly be:

The Sith fortress is hidden from the Light.
Surrender to Darkness to find the way.
To those who embrace it, this blade shall tell.

I don’t think it’s “technically” iambic pentameter, but all of the lines would at least have ten syllables. (Maybe that’s a failure of the translation lol.)