I have just finished the final gym battle against Adam. During this battle I lost a few times yet have now found the ultimate strategy. I used Lv.85 Mew (Hardy nature) and the move Psychic to deal with Greninja the first time, and proceeded to change to Lv.84 Steelix (Lonely Nature and Steelixite (Fire)) to deal with Spiritomb. After this was knocked out, I changed to Lv.83 Hawlucha (Sassy nature). To my delight, by first using Swords dance to increase my attack stat, I was able to knock out EVERY OTHER POKEMON in the battle using just the move High Jump Kick. I didn’t even have to use my Lv.93 D. Charizard for the whole battle. I have been continuously impressed by my Hawlucha - a less talked about Pokémon and think it should be used more often.