Hello there guys! Bato here and I'm making a blog post of my own again.
The Spriggan 12 are said to be a group of twelve extremely skilled Mages in the Alvarez Empire who served as "Shields" of Emperor Spriggan aka Zeref Dragneel and said to be on the level of power with God Serena, an ex-Wizard Saint in 1st rank from the Isghar continent according to Hyberion, the second ranked Wizard Saint himself.
I must say that some of these guys might have been trained and taught how to become badass Mages with godlike Magics (like Brandish in changing topography casually) by Zeref himself since he also taught the four founding members of Fairy Tail (Mavis Vermilion, Yury Dreyar, Precht Gaebolg, Warrod Sequen) Magics that made them formidable Mages of Fiore. Or other members are already formidable Mages in their own right but joined the ranks just like God Serena did.
Since God Serena is now a member of the Spriggan Twelve for reasons unknown why he do that, what happened with the original twelfth member? I wonder if Zeref killed one of the Spriggan Twelve for incompetency to start a war against Isghar in hot blooded idiocy ten years ago and God Serena defected to fill in the void as a new member. Or probably served as a hidden ace in the shadows as the 13th member while the Spriggan 12 are known in the open until the time has come to show himself/herself.
Just stating out my thoughts. That's all. Feel free to comment and have a nice day minna! XD :D