Red, Blue and Green are all in Let’s Go Pikachu and Eevee, coming all the way from the original Pokemon titles. Blue and Green will run into you occasionally along your journey, but Red remains the most mysterious trainer of them all. This guide will show you how to prepare, and battle the Pokemon Master, Red.
Red cannot be battled until after completing the main story and defeating the Elite Four. Afterward, 153 Master Trainers will spawn throughout the entire map, specializing in one specific Pokemon each. To beat them, you must use only the Pokemon that they specialize in, with no items allowed.
After defeating six of these trainers, Red will finally appear. He can be found on Indigo Plateau, directly outside of the Pokemon League.
Similar to the Master Trainers, no items can be used during the fight, and Red is insanely tough. You’ll want to be ready for this one.
After defeating Red, you will officially earn the title, Battle Master.