'Try to find the graves of our fathers, the only things for which we are prepared to fight'

Sometimes you need to comb through historical sources to find gameable material. And sometimes it's just sitting there, staring you right in the face.

From Julian Baldick's Animal and Shaman: Ancient Religions of Central Asia:

'As for Darius' invasion itself, Herodotus relates that the Scythians responded to it with a strategic retreat and a mocking message to Darius to try and find the graves of their fathers, the only things for which they would be prepared to fight.' (p. 21)

All the peoples of ancient Central Asia buried their royal dead in secret. Some kings went to extraordinary lengths to ensure this secrecy: killing the workmen who built the tombs, for example, or having the burial party kill everyone they met along the way to the grave site in order to ensure that no-one was left alive who could describe the route they'd taken. (Both of these also had the useful side effect of providing a whole bunch of human sacrifices for the new ancestor spirit that the recently-deceased king was assumed to have become.) The grave has to be secret, because if it's not secret then your enemies can come and defile it, which means that you have to commit your forces to hanging around guarding a bloody tomb in order to avoid the permanent disgrace of allowing the bones of your ancestors to be desecrated. For a nomadic people which lived or died by their mobility in war, this was a serious liability.

And we're not just talking about holes in the ground, here. Some of these tombs were massive:

'A Khazar king would be buried near a river, which was diverted to flow over the mausoleum. This mausoleum was in the form of a house with 20 rooms, each containing a tomb. The men who had buried the king were beheaded afterwards so that no-one would know which room contained the body.' (pp. 29-30)

You can see where I'm going with this, I'm sure. This is a dungeon complex. Twenty rooms, containing twenty identical flooded tombs, one of which contains an ancient king and the other nineteen contain... what? Traps? Monsters? Undead guardians? The idea that people killed by (or killed for) a king or warrior had to serve him after death was a common one: in a fantasy setting, it might be very literally true, with a king's tomb crawling with the imprisoned ghosts and/or reanimated corpses of all the people killed by him in life and sacrificed to him in death. This kind of spirit-binding was actually attempted historically:

'[T]he inscriptions tell us of a specifically Altaic practise, that of dedicating an enemy (or one of his various souls) to a Türk in the hereafter, in order to serve him. In this connection a special word, balbal, is used to designate both the slain enemy (or a soul of his) and a stone monument which is set up to represent him. Thus the enemy is turned into a balbal: he becomes the stone monument.' (p. 41)

The souls of your dead enemies. Bound into stone statues. Placed all around your giant, secret tomb in order to serve you in the afterlife and defend you against intruders. Seldom has real-world history sounded quite so much like a D&D adventure module.

Balbals look like this, by the way.

The adventure writes itself. Step one: find the damn mausoleum. Step two: fight your way past the animated stone guardians. Step three: enter the haunted tomb-complex and try to figure out which of the twenty tombs inside actually contains the corpse you're looking for. Maybe you're hoping to loot his grave goods. Maybe you need to talk to his ghost. Whatever it is, it had better be really important - so important as to be worth all the trouble you'll need to go through to get it. Because when it came to supernatural tomb security, the peoples of ancient Central Asia did not fuck around.

And best of all, it'll all be completely historically accurate!

Sort of.