Steven, if you still haven't figured out why, he has steel types and the highest is Meatgross, but if you mean best as in the hardest to beat, Cynthia, good variation of pokemon types, good pokemon, not to mention two big threats; Lucario and Garhcomp, also packed up with Milotic which is a wall, and Reoserade a great grass special sweeper, and Spritomb who has above average defences and no weakness "well except foresight + fight attack and that ability that hits ghost with fight moves, forgot it's name tho".