Desperately Balanced

The Big U is full of ideas and references that recur in later books by Neal Stephenson. One of the minor references is Shekondar:

...the Guild generated Shekondar the Fearsome/JANUS 64, the Organism that inhabits and controls the colony. [Keldor died building it].... But out of his death came the King of Two Faces, that which in Techno-Plexor is JANUS 64 and in Magic Plexor, Shekondar the Fearsome.

and then it crops up again in Cryptonomicon:

But Randy does find one [CD] from an evidently Seattle-based band called Shekondar.... Now, Shekondar happens to have been the name of an especially foul underworld deity who played an important role in some of the game scenarios that Randy played with Avi and Chester and the gang back in the old days.

A third reference has popped up in REAMDE, where an MMORPG player by that name is interviewed for the in-game paper:

Steadying himself on an eight-foot wizard's staff as he waded through a knee-high river of blood washing down the market street of Bagpipe Gulch - a community that once prized its status as the "Gateway to Torgai" - Shekondar the Fearsome, a local alchemist, denied that the trend was a negative influence on the town's image, insisting that the influx of "Meat," and the bandits, land pirates, and cutthroats who had come to prey on them, had been a boon to the region's economic development and a bonanza for local merchants, especially those who, like Shekondar, dealt in goods, such as healing potions and magically enhanced whetstones, that were in demand among the newcomers.

The Internet doesn't provide an authoritative source for Shekondar, although it appears to be a popular gamertag with people in the sort of places that I associate with role-playing games, so perhaps it's an old RPG character that is old or obscure enough not to have made the Internet on its own.