The Heart of Caizehl is the city-font of Mhaldor, bestowed upon them by Sartan in the year 807AF.
After the destruction of the Fissure, Mhaldor sought a way to restore their font. Within the depths of the tunnels that Moghedu dug in order to assault the city with aid from the Tsol'teth, a great pit was dug and subsequently filled by Mhaldorians as they sacrificed their life essence and blood in service to Sartan. Once it was sufficiently filled, they sacrificed an Avatar of Evil in order to consecrate it. Sartan then took to battle upon the Inferno where the Demon Prince Caizehl started an uprising over against Sartan's rule. He was ultimately slain by Sartan's hand and his heart ripped out and presented to the city as the new font.