It’s apparently meant to power up GX Era Decks in Duel Links.
Mini Box 7 “Servant of Kings” is being released October 2017
Dark Magician of Chaos and Birthright are included cards in the Set.
[Duel Links] The 7th Mini Box Announced
By NeoArkadia
NeoArkadia
NeoArkadia is the 2nd Number of "The Organization" and a primary article writer. They are also an administrator for the forum Neo Ark Cradle.