[OVERVIEW]

In the first bullet mention that Serperior can accrue boosts and become very strong while chipping at its checks (this is why its a good offensive mon). Next, just because Glare and Leech Seed are good utility options, it doesn't really give Serperior a bunch of different roles on teams since both sets generally do the same thing, even if they're attempting to circumvent Serp's checks and counters in different ways. Don't mention Substitute at all here as well, most mons can learn it so it's not particularly special. The third bullet is kinda fluffy so I think you could stand to cut it down to something along the lines of "Serperior can be a potent late-game threat due to its great 113 base Speed tier, allowing it to outspeed many common unboosted threats such as Terrakion, Latias, Cobalion etc." After this, mention some more stuff like Hippowdon, Krookodile, Suicune, Alomomola. Maybe take out the mention of the Electric resistance since while it does resist it, the common Electric-types aren't super amazing matchups for Serp; Raikou can hit it with +1/2 HP Ice and Pressure stall Leaf Storms with Sub, and Manectric can just pop it with Overheat. Next up on the agenda, don't say that Serp's movepool is barren, since HP Fire and Z-Hyper Beam is basically all it needs to have +2 neutral coverage vs most of the meta. If anything just say that it can be somewhat predictable since it's pretty much always gonna be running the same couple coverage moves. In the last bullet, you say that Serperior is easy to pressure with some common attacking types. I think this is what whoever said this wasn't reflective of the meta was kinda talking about. If Serp was easy to pressure with any old Fire- or Ice-type, it probably wouldn't be S/A+ on the VRs and council vote worthy. Mention that it doesn't get many switchin opportunities against common offensive playstyles, and then when mentioning its type weaknesses, mention some relevant mons that can provide these like Crobat, Choice Scarf Infernape, Chandelure, Kyurem, and Mega Beedrill.

[SET COMMENTS] (SubSeed)
Moves
========

Firstly, make Leaf Storm the first move on this set. The base reason to use Serp is the boosts it gets from Leaf Storm, even if the point of this set specifically is to abuse SubSeed locking slower stuff. Change the bullets' order accordingly. Give give Sub and Leech Seed their own bullets, but do make sure that the reader knows that they should be used in conjunction with each other.

Set Details
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Use the phrasing "maximum EVs in Special Attack and Speed" rather than "the given EV spread". Also say something like "maximizes Serperiors offensive presence. For the bullet about Contrary, after mentioning that its SpA goes up, say "as well as" when going on to mention the Defog and Sticky Web parts.

Usage Tips
========

For this first bullet you could change this to something along the lines of "don't let Serperior take a ton of chip damage" by mentioning to not switch it into multiple layers of Spikes/ Tspikes, or common U-turn or Volt Switch users like Gliscor or Rotom-C. I'd remove mentions of Manectric since switching it into Manectric pretty much results in a bad position for Serp every time. For the second, it might make a little more sense to say "boost Serperior's Special Attack with Leaf Storm" rather than just say "get to +2". For the last bullet, say something a little more coherent than "strong attacks"; you could phrase it like " avoid switching Serperior in to strong attacks as often as possible, as this set particularly appreciates Serperiors longevity".

Team Options
========

First bullet is fine so not much to change there. I do like how you mentioned Poison-types as partners since removing TSpikes for this Serp set is pretty huge, but I'd mention Electrics and Poison-types separately, though not in different bullets(something like mention both types > electic examples > poison examples. Also mention how Electric types like Mega Manectric or Raikou can check Flying-types like Mega Pidgeot and Crobat that Serperior doesn't like taking on, while Serp can come in and take advantage of bulky Ground-types that like to switch into Electric-types. For the Poison-types, the part about absorbing Tspikes is pretty big so make sure you mention that they should be grounded Poison-types that can automatically absorb them, since Crobat won't be helping Serp out much in this regard besides Defog, but it doesn't really wanna be coming directly into the things that would be setting them i.e. Nidoking, Nihilego, Tentacruel. In the mention of entry hazard setters, be sure that you make it clear that Klefki or Terrakion aren't doing the wearing down of Serp's checks, but the Spikes / Stealth Rocks that they set. For the Ground-types bullet, it should probably be changed to "Pokemon that can break Amoonguss". Mamo and Gliscor are both decent, but also mention CB Azu with Ice Punch. There are plenty of other examples that I could think of if I gave it the time, but I'll trust you to come up with a few more decent examples.

[SET] (Z-Move)
 Slash Synthesis and Taunt with Glare, they're all great options.

[SET COMMENTS]
Moves
========

Not much to be said since this is fine overall, just add bullets for Taunt and Synthesis.

Usage Tips
========

Give some examples of Voltturn mons that can bring Serperior in safely, shouldn't be too hard. Also remove the mention of Gliscor in the first sentence, since a large majority of Glscor nowadays are specially defensive with Toxic, and unboosted Serperior doesn't threaten them to the point where they switch out immediately most of the time. Lastly, mention Crobat in the part where you discuss the Glare targets, it's a pretty big one.


Team Options
========

Mention some common offensive staples like Cobalion and Mega Aero in the first bullet. Again, for the third bullet, make it clear that the entry hazards are doing the damage, not the Pokemon themselves. Next up, out of all the good hazard control we have in the tier, Starmie is a bit lackluster at removing hazards compared to stuff like Hydreigon, Mega Altaria, and Gliscor, so maybe mention those instead / alongside it.

[STRATEGY COMMENTS]
Other Options
=============

Dont rag on Defog, it's a solid remover that can pressure stuff like Tentacruel and Swampert a lot. As for Taunt and Synthesis, they're slashed on the second set now so take that out. Serperior is also unable to run Aromatherapy with Contrary unfortunately, so remove that. Mention Giga Drain since it makes Serperior pretty good at beating Suicune since it doesn't solely rely on Leaf Storm to beat it which can easily get messy with only 8 PP. Its also a more proactive way of giving Serperior decent recovery since boosted Giga Drain will still sting anything that doesn't resist it. Also mention Meadow Plate for an alternate item option, since it makes Serp just that much stronger and is a decent choice if you've already got a z move. Lastly, mention Gastro Acid as a way of removing Sap Sipper from Azumarill.

Checks and Counters
===================

Add a section for Flying-types like Mega Pidgeot and Crobat, and make sure to mention that Crobat can bypass SubSeed sets thanks to Infiltrator. Add a section for Dragon-types, since it relies on Breakneck Blitz to bust through them most of the time. CM Latias beats it 1v1, Hydreigon and Haxorus can pressure it a lot, and Kyurem can burn Leaf Storm PP with Pressure and obviously shred it with Ice Beam. Next, add a section specifically for Chandelure, as it resists Leaf Storm and HP Fire, as well as not giving a shit about Hyper Beam or SubSeed thanks to Infiltrator. Lastly, remove "easily" from the section where you mention priority moves, as Scizor and Entei need a good amount of chip to KO with Bullet Punch / ESpeed, and while Mamo's does a lot more it's definitely not a clean OHKO and still does need a signigicant amount of chip which can be hard to get sometimes vs SubSeed / Synthesis / Giga Drain variants.