A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Kyria d'Oreyn
Although he is not directly mentioned, Handar fights the Trollocs and Myrddraal inside the Stone (TSR, Ch. 10). We learn this when he shows his scar to Rand and discloses that he received it while fighting the Shadowspawn.
He is one of the two guards on duty to guard the Heart of the Stone when Rand and his party enter through a gateway from a nearby inn. He asks Rand whether he wants to have the High Lords summoned to his chambers or a guide through the shifting corridors, but Rand declines both.
(Reference: Knife of Dreams, Chapter 21)