Summary[]
This is a picture of Balthazar from Guild Wars.....
The Shadow Knights defended the crypt of Rike Kelborn in the King's Catacombs. There were four in number when the party entered the chamber, but there may well have been others in the other unexplored crypts in the catacombs. The knights made use of their ethereal form by repeatedly teleporting behind the party members with each blow, striking with distinct advantage.
They were insubstantial undead in the same way as Wraiths and other spirits, so mundane weapons could not harm them, as Bregor discovered. Magic weapons, however, proved to be effective.
It is unknown who the Knights were when alive or if they were ever alive at all or simply constructs summoned to defend the crypt. The Knights provided a suitable distraction for Banon to sneak by while invisible to lift the ring from the dead king's hand. This precipitated the events of Week 23 and Banon's demise.