Gyarados @ Gyaradosite
Ability: Intimidate
EVs: 252 Atk / 88 Def / 168 Spe
Jolly Nature
- Dragon Dance
- Crunch
- Earthquake
- Waterfall

Rayquaza @ Choice Band
Ability: Air Lock
EVs: 252 Atk / 4 SpA / 252 Spe
Naughty Nature
- Dragon Claw
- Dragon Ascent
- Waterfall
- Extreme Speed

Arceus-Fairy @ Pixie Plate
Ability: Multitype
EVs: 252 HP / 4 Def / 252 Spe
Timid Nature
IVs: 0 Atk
- Calm Mind
- Judgment
- Earth Power
- Recover

Xerneas @ Power Herb
Ability: Fairy Aura
EVs: 40 HP / 252 SpA / 216 Spe
Modest Nature
IVs: 0 Atk
- Geomancy
- Moonblast
- Thunder
- Focus Blast

Landorus @ Life Orb
Ability: Sheer Force
EVs: 4 Atk / 252 SpA / 252 Spe
Naive Nature
- Calm Mind
- Hidden Power [Ice]
- Earth Power
- Rock Slide

Magearna @ Leftovers
Ability: Soul-Heart
EVs: 252 HP / 4 SpA / 252 SpD
Calm Nature
IVs: 0 Atk
- Heart Swap
- Fleur Cannon
- Volt Switch
- Heal Bell

So this team is for the landorus spotlight - fun team that lets it do its thing by pressuring out necro-duskmane and running its way on an offensive team with its stupid strong earth powers. Rest of the team - Arc fairy + Xern. Lando can punch holes and always keep the necros pdons ho-ohs and magearnas on edge, and set up for sweeps from either mon - though arc serves more as a utility mon that can take on the mences and such of the tier. (Support set can be run instead on this mon). Magearna makes the 3rd and final fairy type - defensive kyogre is an issue for the team to deal with and this helps, as well as stopping xern and arc-fairy on the other side as well. Rounding out the team are 2 offensive threats in ubers, rayquaza, but a unique set with a band and DClaw, DAscent, Waterfall, and ESpeed. V-create is an option over waterfall. Waterfall for PDon, V-create for Necro and Mega Scizor. Adamant banded Dragon Ascent is stupid hard for ubers to deal with and is gonna be the main move to be clicked. Lastly is mega gyarados, DD 3 attacks. EQ is better than taunt imo, lets it sweep much easier in the tier, allowing it to punch through PDon, weakened dialgas and magearnas. Just an underrated mon in ubers and fun to use, jolly because adamant misses out on necro-ultra and mega gar at +1, you can run more speed to outpace mewtwo-Y but thats about it. Basically offense with an arc fairy and magearna. Lando wallbreaks and lets the rest of the team try and sweep. CM can be replaced with Defog or Rocks, as the team lacks both; however if your opponent has an obvious switch such as an arceus form, CM can be a way of just staying in til you die by being able to take a support arceus's ice beam/ super effective hit (unless arc-ice) or any 2 judgements and just send out earth powers to get some damage out before lando dies.

some calcs:
0 SpA Arceus-Water Ice Beam vs. +1 0 HP / 0- SpD Landorus: 272-324 (85.2 - 101.5%) -- 12.5% chance to OHKO
0 SpA Dread Plate Arceus-Dark Judgment vs. +1 0 HP / 0- SpD Landorus: 135-160 (42.3 - 50.1%) -- 0.4% chance to 2HKO
+1 252 SpA Life Orb Sheer Force Landorus Earth Power vs. 252 HP / 0 SpD Arceus-Water: 292-344 (65.7 - 77.4%) -- guaranteed 2HKO
252+ Atk Choice Band Rayquaza Dragon Ascent vs. 252 HP / 64 Def Arceus-Fairy: 289-342 (65 - 77%) -- guaranteed 2HKO
252+ Atk Choice Band Rayquaza Dragon Ascent vs. 32 HP / 64 Def Kyogre-Primal: 364-430 (104.2 - 123.2%) -- guaranteed OHKO
252+ Atk Choice Band Rayquaza Dragon Ascent vs. 248 HP / 8 Def Groudon-Primal: 237-279 (58.8 - 69.2%) -- guaranteed 2HKO
Basically only magearna and necro take 2 dragon ascents in the tier
+1 252 Atk Gyarados-Mega Crunch vs. 252 HP / 4 Def Prism Armor Necrozma-Dusk-Mane: 271-321 (68 - 80.6%) -- guaranteed 2HKO
+1 252 Atk Mold Breaker Gyarados-Mega Earthquake vs. 248 HP / 8 Def Groudon-Primal: 246-290 (61 - 71.9%) -- guaranteed 2HKO
+1 252 Atk Mold Breaker Gyarados-Mega Earthquake vs. 248 HP / 56+ Def Groudon-Primal: 216-256 (53.5 - 63.5%) -- guaranteed 2HKO
+1 252 Atk Mold Breaker Gyarados-Mega Earthquake vs. 252 HP / 4 Def Magearna: 328-388 (90.1 - 106.5%) -- 43.8% chance to OHKO after Leftovers recovery