Warning: contains spoilers for One Piece #1054!
The family of Luffy, One Piece's protagonist, keeps growing more and more dangerous, as Sabo, the Straw Hat captain's brother, is now worshiped around the world for his exploits as a Commander of the Revolutionary Army. After the revelation that Luffy has the powers of the ancient god of freedom, Nika, the fact that Sabo is now known as the "Flame Emperor" means that the tyrannical World Government has to contend against two "gods."
Sabo is the sworn brother of Luffy. Together with Ace, the trio grew up in the Goa Kingdom, dreaming of becoming free-roaming pirates. However, Sabo was supposedly killed while trying to run away from his aristocratic and cruel family. He was actually saved by Monkey D. Dragon, Luffy's biological father and the leader of the Revolutionary Army, who raised him to become his second in command. Years later, Sabo and the other Revolutionary Army commanders infiltrated Mary Geoise during the Levely, the summit of the world's monarchs, to save their friend Kuma, enslaved by the Celestial Dragons (the highest-ranking World Nobles). They were confronted by two Admirals - Ryokugyu and Fujitora - and the outcome of that battle was only recently revealed.
After previously teasing that Sabo had been killed, chapter #1054 of One Piece revealed that the rescue mission was successful, and the commanders managed to inflict a heavy blow on the Celestial Dragons. Sabo's actions resonated so much that he is being called "the hero of the entire world" and "Flame Emperor Sabo" because he ate the Mera Mera no Mi, the fire-based Devil Fruit once possessed by his deceased brother Ace. Sabo is also accused of having murdered King Cobra of Arabasta, a descendant of one of the twenty nobles who founded the World Government. Even if this is unlikely to be true, revolutionaries all over the world were inspired by Sabo to overthrow their monarchs, and they are now worshiping the boy like a god.
This turn of events is even more significant because it comes shortly after the revelation that Luffy possesses the powers of "Sun God Nika," a mysterious mythical figure from the past who was worshiped as a liberator by slaves. The similarities between the two brothers cannot be coincidence. One Piece has strong recurring symbolism, especially regarding the Sun and its related concepts, such as "dawn" and "fire." These always have very positive connotations, usually connected with freedom and liberation from oppression. Sabo and Luffy are both "liberators" in their own ways, who have helped countless people all over the world. The fact that they are both characterized as "gods" now puts them on a clear path of collision with the cruel Celestial Dragons, who define themselves as "the gods of this world."
Considering that Luffy and Dragon also carry the mysterious "Will of D." considered the "natural enemy of the Celestial Dragons," together with Sabo this family is now the most dangerous threat to the World Government. The world of One Piece is quickly moving towards a huge war, and fans can be certain that Luffy's family will be at the center of it.