Tomb of Hakra

The tomb of Hakra has drawn adventurer's to the Calidar Mountains for going on 10 years.  In the early days the Mountains were filled with adventurer's.  In more recent years only a few desperate souls try their luck at it.
Hakra was supposedly a mage from the early days of liberation and it is said he had amassed weapons of ultimate destruction.  One such weapon is Zigmund's sword.  It is said Zigmund paid Hakra 3 carts full of platinum for the blade and after Hakra journeyed into the mountains and was never seen again.  The treasure and weapon hoard is rumored to still remain in his tomb.
The tomb was discovered nearly three years ago.  Upon approaching once is greeted by an image of Hakra speaking in an unknown language.  While the language itself is unknown mages have used the spell comprehend languages to decipher it as a message that entails the tomb awaits those who are worthy to be bestowed Hakra's greatest creation.
The tomb location is well known.  The method of entry remains a mystery.  The entrance is a massive white marbled arch built on the side of the Mountain.  There is no doorway or entry way visible in the smooth black rock wall under the arch.  A series of runic symbols cover the wall.  Some adventurer's are seen to disappear upon examination of the runes while others simply stare at them with no effect.
Efforts were made to blast into the tomb, but the black wall has thwarted the efforts of even the mightiest of weapons and spells.  All damage done to the wall seems to be transferred unto the attacker and increased 10 fold.  Even dispel magic has been thwarted.  Of those who have entered none have returned.