Luesh was steward to House Davar and one of Lin Davar's close confidants. He knew of the Soulcaster kept by Brightlord Davar and for that which it was used. Luesh also knew how to use it and had been trained to do so, but could no longer make it function.
Balat Davar thinks that Luesh was a contact between the people who came for the Soulcaster and his father.
Luesh died in his sleep before Shallan managed to steal Jasnah's Soulcaster. Balat did not think there was any reason to suspect that he had been murdered.
Luesh is thought by Shallan to be one of the Ghostbloods - a secret organisation opposed by Jasnah - due to the symbol he wore around his neck.