Walkthrough: After making it back to Iki Town - having completed Captain Ilima's Trial and helping Lillie - you will face Kahuna Hala in your Melemele Island Grand Trail. Hala is an expert Fighting Type Pokemon User, having the power of Z-Crystals as well. Defeating him will earn you a stamp on your Trainer Passport, forcing traded Pokemon up to Level 35 to obey you. You will also receive Fightingium Z for defeating Hala, as well as the Rider Pager you can use to ride Tauros.
Island Kahuna Hala - Level 15 Machop, Level 15 Makuhita, Level 16 Crabrawler