First, you want an Intimidater NPC. Any one works. This CAN work without one but it's pretty much foolproof if you have one. You can enter alone then run if you don't get one to try again. If you don't have intimidate and he starts with Dragon Claw, you'll need to restart most likely. He USUALLY starts with Boomburst though.
Kommo-o @ Shell Bell
Ability: Soundproof
Tera Type: Fighting
EVs: 252 HP / 252 Def / 4 Spe
Impish Nature
– Body Press
– Iron Defense
– Breaking Swipe
– Protect
- Iron Defense x3
- Breaking Swipe to build Tera
- Tera and Body Press until he resets your stats.
- Protect to avoid the Boomburst
- Iron Defense x3
- Body Press until Win.
Soundproof makes you immune to his special attacks. You have to protect when he resets you to avoid a potential Boomburst.
Other than that it's pretty easy. Have done it 5 times now. The one time without an Intimidater I lost but that was mainly cause he crit me with dragon claw before I had a chance to Tera 🙃
by Fynzou