The Enemy Warrior Arc is unlocking after completing the Super Warrior Arc in the story mode section, along with earning
It is the same basic progression as the Super Warrior Arc, except with a slight change in narrative and playable characters. You start with Frieza and Nappa and go on to be able to use Cell, Ginyu, and most of the Z Warriors.
Androids 18, 16, and 21, as well as Beerus, Goku Black, Kid Buu, Teen Gohan, Future Trunks, and Hit are unplayable in this arc. Most of the fights here will still be pretty simple. If you want to sustain the same characters during each chapter, I would recommend using Health Regeneration, Victory Health Recovery, Attack Up, or Defense Up. As before, after each boss fight, the chapter ends. You unlock the achievement after defeating the final boss.