King the Conflagration is an All-Star of the Beasts Pirates as one of Kaido’s three closest confidants, the Disasters. He’s supposed to be the strongest Disaster.
King is part of a yet-to-be-identified race. Big Mom stated she would forgive his transgression on her if he joined her crew, since he is part of a unique race that she wanted in Totto Land, but he bluntly refused.
My theory is that King is a Kotengu.
We know that Tenguyama Hitetsu resembles a Daitengu so it would make sense to have King be a Kotengu as they have black wings and are usually more evil and crowlike.
Also, according to the myths Kotengu enjoys torturing humans and King has been described as a torture loving pervert and a Daitengu also would fit with the theme of Wano and the other yokai we have seen and the fact Big Mom thought the race was extinct.
*Theory by Anxious-Science