I'm in favor of quick banning Darmanitan but I feel like one of it's best counter isn't being talked about enough. On my stall teams I like to use Centiskorch as my Darmanitan answer because using bulky waters just doesn't work when they get worn down by U-Turn and also need to be able to answer Dracovish.
Centiskorch @ Heavy-Duty Boots
Ability: Flash Fire/Flame Body
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Fire Lash
- Knock Off
- Rest
- Sleep Talk
Scarf
252 Atk Darmanitan-Galar Flare Blitz vs. 252 HP / 252+ Def Centiskorch: 130-154 (32.1 - 38.1%) -- 96.3% chance to 3HKO
252 Atk Darmanitan-Galar Earthquake vs. 252 HP / 252+ Def Centiskorch: 108-128 (26.7 - 31.6%) -- guaranteed 4HKO
252 Atk Darmanitan-Galar U-turn vs. 252 HP / 252+ Def Centiskorch: 38-45 (9.4 - 11.1%) -- possible 9HKO
Band
+1 252 Atk Darmanitan-Galar Flare Blitz vs. 252 HP / 252+ Def Centiskorch: 195-230 (48.2 - 56.9%) -- 91.8% chance to 2HKO
+1 252 Atk Darmanitan-Galar Earthquake vs. 252 HP / 252+ Def Centiskorch: 163-192 (40.3 - 47.5%) -- guaranteed 3HKO
+1 252 Atk Darmanitan-Galar U-turn vs. 252 HP / 252+ Def Centiskorch: 57-67 (14.1 - 16.5%) -- possible 7HKO
The main problem with checking Darmanitan is you'll get worn down by U-Turn, which Centiscorch handles better than the other answers. It has access to Flash Fire, so you don't have to worry about the Flare Blitz calcs, however when I pair it with Dugtrio I actually prefer Flame Body. Obviously the chance to burn is nice and if Darmanitan does hit you with a Flare Blitz the recoil will put it into Stone Edge range as well as Centiskorch's Fire Lash if you weren't able to have Stealth Rocks up to do so.
Centiskorch isn't worthless outside of this role either. It counters Excadrill without a Rock move, Physical Aegislash without Head Smash and Leftovers Special sets, Cinderace with Flame Body. It also beats Bisharp, Conkeldurr, Corsola, Ferrothorn, Grimsnarl, Mandibuzz and Mimikyu
If you looked at Jellicent you would see it actually handles Darmanitan better but you lose the ability to kill it back and just sponge the hits until you're eventually weakened and killed. Depending on Jellicent, while a better counter places to much of a restriction on team building. You usually need your water Pokemon to handle Rain, Dracovish, and Cinderace and Darmanitan pairs well with all of these.
Having two pokemon that can reliably check it is not enough when we can see how well it performs in every single game. It's just stupid how easy it is to win with Choice Band Darmanitan on a rain team. I do however see an argument that if Dracovish were banned there'd be less heavy team building restrictions making it easier to handle Darmanitan but if Darmanitan is banned Dracovish will become better without every team having scarf Darmanitan to revenge kill it. If Dracovish is currently considered to restrain teambuilding enough to warrant a suspect then I believe it could make sense to suspect it before Darmanitan and if banned evaluate the meta from there.
Having said all that I'm still in favor of quick banning Darmanitan. If Dracovish is suspected first, not banned then Darmanitan is it would lead to having to probably do another suspect of Dracovish. I am against suspecting Darmanitan because it is overwhelmingly obvious that it is broken in the current meta, but if you don't care about time wasted suspecting it it would make more sense to be thorough and start with suspecting Dracovish.
If the mods don't want a discussion on how Dracovish restraining teambuilding makes Darmanitan harder to deal with I'll remove that section and leave this talking about Centiskorch. However if such discussion isn't allowed I really don't see the point of this thread. Darmanitan is easily broken enough that everyone knows it deserves at least a suspect so spending 1-2 weeks deciding if gets suspected or quick banned seems wrong when a suspect test could have just been started right away,