It's the same as every primal. You had to kill Ifrit, Titan, Garuda, Moogle Mog, Leviathan, Ramuh, Shiva, Ravana and Bismarck during the storyline.
Yet, none of the EX version are part of the MSQ.

The difference is that, to acces the EX version, you don't need to do the story version...That's a first.