Arceus in Ubers UU
I have felt for a while that
is too strong for this tier. There are many reasons why it should leave the tier, but there are also many reasons it should stay in this tier. (Remember that this is just my opinion as an individual and not a reflection of the council's opinions as a whole, and you’re free to disagree and discuss in the thread below.)Its versatility
Arceus is incredibly versatile in almost every sense. Need a specially defensive Fire-type with recovery? Say no more
. Need an offensive Dark-type sweeper? Go for it, 
. Luckily, Team Preview tells you what Arceus form your opponent has, but that doesn’t remove the entire guessing game. Multiple Arceus formes have multiple sets, and these can range on any side of the attacking spectrum, with most status moves, such as Will-O-Wisp or Thunder Wave, almost any coverage move it desires, such as Earth Power and Extreme Speed, and can setup in many ways. All of this is bolstered by...Its stat distribution
Arceus has a pretty simple stat spread. 120 in every stat. It cannot be understated how much of a privilege this stat distribution is. It allows the offensive Arceus formes to be incredibly bulky still, and it makes defensive sets an absolute nightmare to KO. Coupled with its good longevity with Recover, this Pokemon becomes a living nightmare to deal with. Nothing short of
Choice Banded Wave Crash or 
Hydro Pump can 2HKO neutrally. It means that a lot of games have Arceus-on-Arceus action, as it's the safest way to handle the opposing Arceus. This leads into my final point against Arceus in this tier, which is...The lack of safe answers
Combining both of the previous points leads to a natural answer. How do you safely answer the opposing Arceus, especially when you factor in terastallization? Effectively nothing can safely wall arceus forms. Sure
beats special Arceus formes until it pulls out Taunt. 
can wall physical variants, but what if it runs Grass Knot? The boundless versatility often means that the Arceus forme can get the element of surprise on you, and that's all this Pokemon needs to sweep. All of these combined make me feel like most of the Arceus formes are too strong with their lack of exploitable weaknesses and boundless versatility. Specifically, I feel like Arceus-Fire, Arceus-Dark, Arceus-Poison, and Arceus-Electric are all inherently too powerful for this tier. Although it is expected for tiers above OU to be overcentralized, I feel the complete lack of options to safely answer all of these Pokemon warrants some looking into at the minimum, but I would like community opinion on this matter. However, there are a few very strong reasons for Arceus to be allowed in this tier. Let's look at these.The lack of an Ability and Item Slot
This, in my opinion, is the main balancing factor for Arceus in this tier. It has virtually no ability, which isn’t super significant but means it misses out on certain unique factors that other Pokemon are afforded by their abilities. However, the big factor for me is the lack of an open item slot. This means no power-boosting items, like a
; no speed-boosting items, like a 
; and most importantly, no 
or 
. This means that Arceus is susceptible to Hazard Chip damage and being forced to Recover and give the opponent a free turn. Alongside this, I feel that this removes some of the unpredictability that Arceus could have had had it been afforded an item slot. The lack of an item slot gives you a chink in the armour, so to speak, something to aim for when trying to counter most Arceus forms, and this leads into my final point.Passive Damage
I feel that the most realistic and safest way to deal with the Arceus formes is to force as much passive damage on them as you can, akin to Gen 5 Ubers. Stealth Rock, Spikes, Toxic Spikes, Leech Seed, Burn, Poison, Toxic, and even Sandstorm all help to deal with an Arceus. I feel this is so mandatory and important to dealing with Arceus that Pokemon like
and 
will stay in on Arceus formes they’re weak to, just to fish for status on them, and the Arceus user will potentially not switch in directly just to avoid this. Passive damage greatly influences the way an Arceus must play.Conclusion
In conclusion, I feel that Arceus is too centralising in this metagame to be healthy, at least with certain forms for sure. I feel Arceus-Fire and Arceus-Electric to be particularly egregious, as they are very offensively threatening, and their checks usually are other Arceus and very specific pokemon, but Arceus-Fire especially feels too strong and far too volatile.
or 
who can often stop it in its tracks because it struggles to break through them even with Tera. I also cannot fathom to imagine the idea of NDW on the tier without Arc Dark
has been a lot more manageable, but that is mainly because people for some reason spam it like an Ekiller with stab + EQ (walled by Skarmory, D tier at best) instead of actually tapping into its potential. I used to dislike this mon because it felt like whenever you saw it you could never tell what it was going to do. However, on the previous stats, about half of all arc poisons run SD Espeed, meaning it is a lot more telegraphed than before. I think this has the potential to be banworthy, but it needs severe experimentation. using Ekiller is not it folks
made 
so much worse, since its biggest check gone from most teams due to it being a defensive liability. It is still strong even now, and it is incredibly cheap to win games with it. Like I swear sometimes I just sac a mon, click SD and win on the spot. It is incredibly stupid. I'm open to suspecting it if enough community support is shown, in posts like this and on future surveys.
answer it perfectly with or without Tera. It would force it to run liquidation which is very bad because then mons like 
and 
begin to be amazing answers to it. It is spread very thin.
