Fire raged around and within what remained of Ackster. After his body evaporated, all that could be called part of his existence was a drooping marble of Ichor. However, the heat outside Ackster's body couldn't compare to the one inside Smelting Furnace.
It took a while, and Ackster would have died if not for Limit Breaker and the reinforcement his Ichor had undergone during Mastrax's experiments.
But Ackster would have died if not for many reasons during his journey. It was barely worth mentioning.
As soon as Smelting Furnace devoured the Core flame and stole its heat, Ackster redirected the power of Limit Breaker toward Stubborn Well-Being. The ordinary Smelting Furnace was enough to deal with the ramifications of stealing from the world's Core.
The heat leaked out of Smelting Furnace when Limit Breaker stopped supporting the walls. But it was because the skill had yet to adapt and refine materials to fortify itself. That would happen in due time.