The Brass Orb made it’s first appearance in ‘Episode 8: Enter the Wolf Rock Part 4‘. I’m fairly certain the gang had no idea just how important this discovery actually was.
The Orb was found at the top of the Wolf Rock, floating in one of the eyes of the mountain with swirling blue mists surrounding it. When Tarek Faelan reached out towards the Orb, the mists encircled him and he disappeared.
At this point, I’m fairly certain the gang promptly forgot all about the Orb until ‘Episode 23: A Shimmering Tear‘, when the orb was used to close down a portal at the bottom of an old mine shaft.
It has since been revealed that, according to legend, there are 3 such Orbs in existence. Each of the Human, Dwarven and Elvish armies held and protected one Orb during the War of the Bloody Priests. It is said that the Orbs were used as power sinks to destabilize these portals and banish the demons back to the Abyss.
This Brass Orb is the one held by the Human Army, led by Tarek Faelan of Clan Eld. The other two Orbs were held by the Stonefist Dwarves and the Elven House of Stormwood.