You must beat 4 Trainers from the Gym to reach the Gym leader.
Rewards: Effect Veiler x2
Gym Trainer Pool (you may challenge and beat 4 of any of these trainers to face the gym leader):
Patrickx31, TheDavyStar, HAIRDO, DarkmagicPikachu, original dueling
Rewards: Effect Veiler x2
Gym Trainer Pool (you may challenge and beat 4 of any of these trainers to face the gym leader):
Patrickx31, TheDavyStar, HAIRDO, DarkmagicPikachu, original dueling