The one who was called the Flame Master, Bargan Hevifield, didn't have any noteworthy masters except for the principal of the Ladro Institute, which was in the shackled realm.
But it's nothing; the commander even had confidence that he could defeat the principal, yet in front of Bargan he stood no chance. Bargan, who tapped the power of flames too deeply, even managed to earn praise from various Gods of Fire.
In the battle in Ladros City, Bargan alone fought several seven-circle officers of the Deadly Sins, yet he managed to defeat most of them. Those officers from Deadly Sins had blessings, and they were equipped with orange-grade equipment and above. But they still couldn't kill Bargan, and they only managed to seal him.
And that wasn't even Bargan's full power.