The team was built around an idea I had sometime between all the leaks and the release of USUM, Blacephalon seemed really silly and I wanted to try it out as soon as possible. As noted before I had no knowledge of how the Battle Tree worked at the time, excluding some casual play during car rides in SuMo, and that they couldn't have Tapus or Ultra Beasts, so the team is terribly un-optimal.
Blacephalon @ Choice Scarf
Ability: Beast Boost
Level: 50
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk
- Mind Blown
- Shadow Ball
- Overheat
- Hidden Power [Ice]
Using Blacephalon was the entire purpose of the team, so naturally he was added first. I didn't know how Mind Blown recoil worked so for future runs, do not use 4HP. I chose Modest over Timid because this Blacephalon is also needed for VGC, where you'll (probably) never need to run Timid on a Scarf set, after doing actual research on Pokemon sets I'd run Timid in the future to jump Garchomp3 and potentially Manectric4. I clicked Overheat once, and it wasn't necessary to my win, definitely replaceable. HP Ice was specifically for killing lead Salamence/Garchomp/Dragonite then switching out to come back in later and clean, it did its job.
Medicham-Mega @ Medichamite
Ability: Telepathy
Level: 50
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Fake Out
- High Jump Kick
- Zen Headbutt
- Helping Hand
The second half of the initial strategy, the idea came to me based off a cheesy Mega Glalie team I made years ago. I gave it 4HP without thinking about missing HJK twice, I think it actually happened once as well... Fake Out breaks Sturdy and Sashes, can stop a potential Trick Room or Sucker Punch, or just gives Blacephalon a free attack in other scenarios. I was lucky I never missed HJK when it mattered, if I used Medicham again I'd replace it with Low Kick, as it gives a very favorable chance to KO Ttar3 with the Mind Blown double target, and gives it a 100% way to OHKO Terrakion. Zen is bad, Medicham only needs to deal enough damage to clean up KOs that Blacephalon and co. miss, would replace with Psycho Cut for a future run. Helping Hand was really good, outside of giving Blacephalon a pseudo Specs it also allowed my Tapu Lele to OHKO Mawile3&4 with Shattered Psyche, no complaints.
Tapu Lele @ Psychium Z
Ability: Psychic Surge
Level: 50
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Protect
- Psychic
- Moonblast
- Dazzling Gleam
I needed 2 back Pokemon to round out the team, Lele immediately jumped at me because it seemed to have solid synergy with both my frontline Pokemon. I don't regret running fast Lele, but the overall spread is something I do, in the future I'd drop it to the empty 160 speed tier, run 108 SpAtk to OHKO Mawile3&4 with HH Z-move, then dump the rest in HP and 4/4 defenses. The only move to talk about it Dazzling Gleam, I didn't think I'd need to use Taunt as I didn't see Trick Room setters in the back as a threat on paper, while I did use it a few times I don't think it impacted the battles so much I would have lost without it.
Tornadus @ Psychic Seed
Ability: Prankster
Level: 50
EVs: 244 HP / 228 Atk / 4 Def / 4 SpD / 28 Spe
Adamant Nature
- Protect
- Acrobatics
- Superpower
- Tailwind
Lastly I needed to fill speed control, Speed reduction seemed meh and Trick Room was out, so I went back to something from SuMo BSD I was familiar with. I wanted to creep positive base 70s, specifically Breloom for a reason I can't remember, possibly because it was an easy benchmark to hit. The bulk actually allowed me to survive some random hits and clutch out a few games, the only one I really remember is Rock Slide from something after chip damage though. All of the moves were necessary, Superpower saved me against some Tyranitar when HJK missed and against a Bronzong.