Oda has recently introduced the God’s Knights, a group in the World Government’s employ, operating in Mary Geoise. According to Fleet Admiral Sakazuki, they are the law enforcers of the Holy Land, above the Marines.
When Dragon brings up the God’s Knight, in the background is the same type of swirls that we’ve only seen when Kaku and Kalifa obtained their devil fruits and ate them.
I think it’s highly unlikely Oda decided to randomly use this background.
ll of the God’s Knights will have extremely powerful Devil Fruits