Serra was easy in older epsodes. She got "buffed" post 17. Still though, she is completely unimportant. Some of her pokemon like Alola Sandslash are terrible, both stats and typing wise and her ace (frosslass) plus main tricks, are niche and situational. If for example, the evasion boost doesn't keep cutting it for frossy, it isn't hard to KO with a single move. Mirror arena also, reflects back your special attacks whenever they fail, sometimes and boosts the evasion of some of your own pokemon, also. Last but not least, a well placed Earthquake/Bulldoze at the start, shatters the damn thing c