#0800 · Gen 7 · Legendary

Necrozma (Ultra) — Best counters

Weaknesses

bug×1.60ghost×1.60ice×1.60dragon×1.60dark×1.60fairy×1.60

	Pokémon	Fast move	Charged move	Weather	Score
1	Eternatus	dragonDragon Tail	dragonDynamax CannonELITE	Windy	10014.6
2	Rayquaza (Mega)	dragonDragon Tail	dragonBreaking SwipeELITE	Windy	9513.9
3	Eternatus (Eternamax)	dragonDragon Tail	dragonDynamax CannonELITE	Windy	9013.2
4	Gengar (Mega)	ghostLickELITE	ghostShadow Ball	Fog	8913.0
5	Garchomp (Mega)	dragonDragon Tail	dragonBreaking Swipe	Windy	8512.5
6	Salamence (Mega)	dragonDragon Tail	dragonDraco Meteor	Windy	8212.0
7	Absol (Mega)	darkSnarl	darkBrutal SwingELITE	Fog	8111.8
8	Kyurem (Black)	dragonDragon Tail	iceBlizzard	Snow · partial	7911.6
9	Gardevoir (Mega)	fairyCharm	fairyDazzling Gleam	Overcast	7811.4
10	Banette (Mega)	ghostHex	ghostShadow Ball	Fog	7711.3
11	Blacephalon	ghostAstonish	ghostShadow Ball	Fog	7611.1
12	Palkia (Origin)	dragonDragon Tail	dragonDraco Meteor	Windy	7611.0
13	Tyranitar (Mega)	darkBite	darkBrutal Swing	Fog	7410.9
14	Sceptile (Mega)	bugFury Cutter	dragonBreaking Swipe	Windy · partial	7410.8
15	Palkia	dragonDragon Tail	dragonDraco Meteor	Windy	7410.8
16	Heracross (Mega)	bugStruggle Bug	bugMegahorn	Rainy	7410.8
17	Kyurem (White)	iceIce Fang	iceBlizzard	Snow	7410.8
18	Salamence	dragonDragon Tail	dragonDraco Meteor	Windy	7310.7
19	Pheromosa	bugBug Bite	bugBug Buzz	Rainy	7310.6
20	Latios (Mega)	dragonDragon Breath	dragonDragon Claw	Windy	7310.6

Necrozma (Ultra) is weak to Bug (×1.6), Ghost (×1.6), Ice (×1.6), Dragon (×1.6), Dark (×1.6), Fairy (×1.6).
Watch its Water/Normal moves — counters like Blacephalon and Tyranitar (Mega) take super-effective damage from them.
Windy weather boosts Dragon moves ×1.2 — the best time to battle Necrozma (Ultra).

Rankings are estimated cycle DPS (attack stat × move damage ÷ cycle time, with STAB and type effectiveness). Not a full battle simulation.