Gabriel called the Infernal King to help him, but the Infernal King refused. Instead of wasting even more spiritual strength to force the Infernal King, Gabriel went to fight alone, using subtle manipulation as well to influence the Infernal King subconsciously.
Fortunately, his plan succeeded as the Infernal King came to help him against the Headless Mage.
It was the first time that Gabriel saw the Infernal King fight, and it was l overwhelming. The attacks of the Infernal King were strong, but his defense was just as good. What was even more interesting was that his flames seemed to have a life of their own.
Moreover, Gabriel was also able to sense that the Infernal King's flames often changed colors along with their properties. The angrier he was, the darker his flames became.
Even the Headless Mage wasn't able to stop the Infernal King once he decided to help Gabriel. The Infernal King destroyed the Headless Mage, helping Gabriel.