This article contains spoilers for The Wheel of Time season 3, episode 4. Dragon Reborn, but he is also the Car'a'carn - the one destined to redeem the Aiel from an oath they broke long ago. But first, of course, he needs to learn why they need redemption in the first place.

In order to do this, he must through the glass columns of Rhuidean. These were created long ago by an Aes Sedai named Latra, who saw them as a judgment upon the Aiel, because anyone who walks between them learns their ancient shame. But how do the columns of Rhuidean work?

The Glass Columns Are Ter'angreal

We've Seen Very Similar Things Before

The glass columns are ter'angreal, objects created by the One Power that do not require use of the One Power to be used. Most ter'angreal are small items, such as the a'dam used by the Seanchan to enslave channelers. But we have seen larger ones before; the Arches in the White Tower are a perfect example. The glass columns serve a different purpose, because they allow any Aiel to catch a glimpse of their past, witnessing events through the eyes of their ancestors.

Ter'angreal are rare, because the Aes Sedai have forgotten how to make them. The glass columns were created back before the knowledge was lost, and they led the Aiel to abandon Rhuidean, unable to cope with the knowledge they impart. Only their leaders and Wise Ones through them, and two-thirds of those choose to kill themselves. Rand ed one Aiel who tore his own eyes out rather than see the visions.

Why The Glass Columns Marked Rand With Two Dragon Tattoos

They Point To The True Nature Of Time

Any male Aiel who successfully es through the glass columns is marked with a golden dragon tattoo, but the Car'a'carn - as the Chief of Chiefs - gets two. This suggests the columns are not only bound to the past, but also to the future; that they can somehow perceive Rand's destiny as well as his history. The idea makes sense, given the franchise's very title - "The Wheel of Time" - suggests history is cyclical in nature in Robert Jordan's world.

The books hinted that some ter'angreal, such as the glass columns, may actually possess a degree of sentience. Aviendha touched one of the glass columns in The Fires of Heaven, and had a unique experience:

"She sensed the powerful aura of the pillar. It was far more potent than any of the ter'angreal she had handled with Elayne. Indeed, the pillars seemed... alive, somehow. It was almost as if she could sense an awareness from them. That gave her a chill. Was she touching the pillar, or was it touching her?"

If the glass columns are indeed sentient, then Rand is presumably the one they chose as the Chief of Chiefs - manipulating the future of the Aiel rather than just revealing their past. That's a chilling possibility that The Wheel of Time books never truly explored.