The Smelting Furnace had already reached its limit in the face of the blue sun's domineering and seemingly endless power. Without Limit Breaker, since the soul shard symbolizing the skill had lost its shine, the Smelting Furnace didn't have any way to resist the blue sun long enough for the liquid Stone of Wisdom to finish what it was doing.
It looked like the liquid Stone of Wisdom was reusing the broken pieces of Ackster's soul to reshape it with itself as the magic glue and patching over the holes from the missing pieces.
But that was no simple task, even for something as mysterious as the Stone of Wisdom.
Ackster's soul was already in a state worse than death. He would have succumbed to his injuries even before his soul shattered. Without a part of his body to heal back from, Ackster wouldn't heal. So, as soon as all of his body was naught but ash, he was as good as dead.
