Ghost/Fairy Mismagius was such a disappointing rumor. I was so excited for it to be true :( Anyways....
- What kind of role will Mismagius take? Utility check to offensive threats such as Garchomp, Landorus, Dragonite, and Kyurem-B, or stallbreaker with Taunt + Nasty Plot?
Although Mismagius gains quite a few resistances and useful immunities, I still don't see it veering towards any defensive sets, simply because it has absolute shit defense and a very poor HP stat. It could potentially be a neat Stallbreaker with its access to Taunt, and with Will-O-Wisp it becomes one of the best checks to most of the physical Dragon-types in OU thanks to its Dragon- and Ground-type immunity. I honestly think its best set would just be a Nasty Plot + Sub set or Nasty Plot + Taunt as mentioned in the OP, because it is able to set up on a whole bunch of stall Pokemon. While its Special Attack is a bit average, its Speed stat greatly makes up for it by putting it ahead of a large majority of the metagame, and after a Nasty Plot boost it's going to be hitting pretty hard. It finds many setup opportunities thanks to its amazing typing and ability. I don't necessarily think that this alone would make Mismagius a top tier threat like Gengar, but it would give it a niche on certain teams for its ability to check Dragon-types so well and sweep lategame, which isn't something that Gengar tends to do.
- How will Mismagius's presence influence the other offensive Ghost-types of OU, Aegislash and Gengar? Will they drop in usage to make room for Mismagius or will Mismagius remain a niche Pokemon?
As I mentioned earlier, I don't think Mismagius' presence would cause Gengar to drop too much in usage, simply because Gengar is used more for the incredible amount of pressure it puts on offensive teams thanks to its powerful STABs and huge coverage with decent utility. It's naturally high Special Attack makes it more of a threat right from the get go, and its slightly higher Speed allows it to check a few more Pokemon. Besides, if Mismagius were to become popular, Gengar is actually a really good check to it, which means that it might actually get even more usage because of that. Aegislash a bulky wallbreaker that checks many different threats that Mismagius couldn't even dream of taking on, such as most physical attackers, so I don't think it would drop much in usage either. Mismagius would probably cause both of them to drop a tiny bit, but not much at all, because Gengar and even Aegislash are actually decent checks to it, making them more useful. Mismagius would be a great addition to most offensive teams because of its ability to check Dragon-types so well, but Gengar and Aegislash both provide incredibly useful support for these teams as well.
- What kind of playstyle will Mismagius's presence benefit and hurt more?
Mismagius would benefit offense a ton. The ability to check a majority of the Dragon-types in the tier with just one Pokemon is amazing, and it has great offensive presence on top of that, so I could see it having a solid niche on offensive teams in need of a Dragon- or Ground-type check. Unless Mismagius carries Taunt or Substitute, stall teams aren't THAT hindered by Mimagius' presence, because Chansey or Blissey with Toxic completely walls it otherwise. However, with Taunt Mismagius completely shuts down the blobs and most stall Pokemon in general, allowing it to sweep very easily once Pokemon such as Mega Venusaur are gone. Most offensive teams wouldn't really worry too much for Mismagius either, simply because Genesect, Excadrill, Scizor, Bisharp (easily OHKOs with Sucker Punch even with Fairy-typing), and Gengar are everywhere. Most bulky offence teams carry Scizor as well.
- What will Mismagius's most successful set look like, and how many effective sets will it have?
Mismagius @ Life Orb
Ability: Levitate
EVs: 4 HP / 252 SAtk / 252 Spd
Timid Nature
- Nasty Plot
- Shadow Ball
- Dazzling Gleam
- Taunt / Substitute / Will-O-Wisp
This would probably be the best set it could run. Taunt makes it a nightmare for defensive teams, while Substitute makes it a huge threat for offensive teams, while protecting it from status and revenge killing. Will-O-Wisp is always an option to give it some useful utility against many physical threats, such as Garchomp, Dragonite, Landorus-T, and Kyurem-B, allowing it to set up on them with ease and supporting its team in the process. I don't really know why people are suggesting Thunderbolt, because it doesn't really hit anything significant that Shadow Ball and Dazzling Gleam don't already; Ghost- and Fairy-type has perfect neutral coverage. What nice about this set is that it's able to set up on so many different Pokemon, which is why I think this set would be its best option in OU.
- Which Pokemon would benefit the most from Mismagius's new found viability in OU, and what Pokemon would be hurt the most?
Basically any team that hates Dragon spam or Ground-type attacks, will appreciate Mismagius. Ironically, it pairs well with Dragon-types because it is able to check Landorus-T and opposing Dragon-types which threaten them. CB Talonflame is another great offensive partner because it checks Mega Venusaur with ease and Mismagius can easily wear down opposing teams, allowing Talon to clean up lategame. On the flip side, Dragon-types will take a huge hit, Garchomp in particular, who will be forced to run something silly like Iron Head to reliably get around Mismagius. Dragonite is also in a world of hurt, because the DD and CB sets are COMPLETELY walled. Nearly every offensive team would need a reliable answer to Mismagius if they decide to use a Dragon-type, or else they'll find themselves being complete setup fodder.
Overall, Mismagius would be a very cool addition to the OU metagame. I don't think it would be as incredible as Aegislash and Gengar, but a huge threat no doubt. It has some very interesting traits that would give it a solid niche in the OU metagame, but its subpar defensive stats and slight competition from other Ghost-types would mostly likely keep it from being top tier. Definitely solid OU though no doubt.
