The thousand-year cold iron was very rare and precious. This kind of iron originated from extremely cold places, and it carried low temperature by itself. It would require a very high temperature to melt. Thus, the control of the temperature must be very accurate. Any mistake would damage the coldness of the cold iron itself.
"The body of the Remnant Ice Sword is extremely thin. It's a problem for us now to cool it down and forge its shape. If we place it into ice water for immediate cooling, the sudden change of temperature may break the sword. If we cool it down slowly, the shape of the sword body may be altered during the process."
The incharge had a very bad headache thinking about the problem. The shape of the Remnant Ice Sword had been forged earlier on. However, they could not find a way to cool it down as the body was too thin. They had dragged on for a few days now. If they continued dragging on, the special property of the ice iron might be damaged.