Alright, guess we're doing this

Fuck this mon, let's talk counters.
First, we establish a set. Tornadus-T can run a bajillion different sets, from support to AV to offensive pivot. But the most common set is almost undoubtedly going to be its Nasty Plot variant, as shown below. This will be the one we're basing calcs off of, as it's easily the most offensively threatening of all the potential sets Torn can run. Everything said will also be assuming you switch in on a nasty plot from predicting the switch, so calcs will be at +2
No. 1 -
We nearly lost this as well, which would've been disastrous in the face of such a monster threat dropping right before NDPL (I agree with Runo, fuck OU why now of all times?). Unfortunately, we have issues here. The only way Slowking Galar can stand up to offensive Torn at +2 is with an Assault Vest, so you're immediately locked out of some of its great utility in chilly reception and toxic spikes. Okay, that's not terrible at least. Second, Glowking can only just about do over 50% to offensive with ice beam. Alright, this is still fine, at least it lives two hurricanes at +2 so it can basically sacrifice itself for a 1-1 trade. Thirdly, knock variants not only remove assault vest but also put it in range of +2 hurricane along with rocks chip. ....Now we have a problem. Torn now either nukes with hurricane or switches out, then uses its plethora of opportunities to come in on various threats it beats, clicks nasty plot and beats you next time around. Have fun!
So not a full counter, though at least it's a check. But this is before you consider pursuit support, which can very easily remove Glowking from the equation.
No. 2 -
Hey another reason for this mon to be on every team. But, as I'm going to be saying a lot in this post I think, we got yet more issues. Issue 1, basically every torn will be running heat wave. This is fine on its own, you live a +2 heat wave, hit a leech seed, click protect, you live a second +2 heat wave just barely thanks to leech seed and leftovers and click heavy slam, doing just barely enough for a kill. Issue 2, your counterplay is so linear and forced that torn clicks nasty plot on the turn 2 protect and now you die to the second heat wave. It's a prediction, but not a hard one by any stretch.
Not a counter, let's keep moving
No. 3 -
No preamble here, the issue is obvious. Focus blast just OHKOs even specially defensive variants. Wonderful. Obviously having to rely on focus miss sucks, but it's not a stretch to say that this means standard defensive TTar is out. No, what I'm talking about is Assault Vest or Chople Berry TTar. Yes, I am that desperate for a counter. Rock blast only needs a little chip for an OHKO, or stone edge just nukes it out of the sky, so take your pick of rock STAB.
Aaaand it's u-turn and now you've come in, taken chip, and don't beat it any more.
...
Next!
No. 4 -
Now we're maybe onto something, although we're scraping the barrel a little due to rotom's less than favourable match up into our more common rockers. Rotom heat is able to survive repeated hits from +2 hurricane and heat wave, while only barely being 2HKOed by focus miss, which is better than an OHKO at least? Gives you a chance to do something, and it's less of a stretch to assume that one of two will miss. You can also take advantage of torn's regenerator ability yourself with pain split, leaving the door open for a pain split + wisp/defog + overheat + volt switch/discharge set. The big issue here is that you're dealing with heavy four move slot syndrome, and the second is that a knock torn is very easily able to wear down rotom by forcing it in, removing its boots, then forcing it in later under rocks from the likes of hippowdon and ttar coming in on the overheat aimed at torn. If you're wisp, you're not defog, or if you're wisp and defog you aren't pain split. Any and all of these combinations lose in one way or another, either by being unable to beat many of our common rockers or by the lack of recovery being unable to withstand repeated assaults. But it's better than what we've been through so far at least.
No. 5 -
.....Okay I know I said I was desperate, but dear god. Torn has no immediate way through Diancie, and flyinium-Z sets don't appreciate rocks massively limiting its regenerator. But you have to rely on passive recovery from leftovers, which can be removed by knock variants, massive vulnerability to the good steels in the tier like Aegislash, Steela and Treads, and such pitiful power that you're barely going to be able to do anything to the rest of the tier. But it beats Torn. So that's something I guess.
Honorable mention to calm mind Blissey as well, being used over chansey since it's less knock weak, which technically wins? But is stall only, hates repeated assaults, can be pursuit trapped, loses to taunt variants, and is now complete fodder for any ghost.
Thank you OU. Please ban this.

Fuck this mon, let's talk counters.
First, we establish a set. Tornadus-T can run a bajillion different sets, from support to AV to offensive pivot. But the most common set is almost undoubtedly going to be its Nasty Plot variant, as shown below. This will be the one we're basing calcs off of, as it's easily the most offensively threatening of all the potential sets Torn can run. Everything said will also be assuming you switch in on a nasty plot from predicting the switch, so calcs will be at +2
Tornadus-Therian (M) @ Heavy-Duty Boots / Flyinium-Z
Ability: Regenerator
Tera Type: Flying
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Nasty Plot
- Bleakwind Storm / Hurricane
- Heat Wave / Focus Blast
- Focus Blast / U-Turn / Knock Off / Superpower / Taunt
Ability: Regenerator
Tera Type: Flying
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Nasty Plot
- Bleakwind Storm / Hurricane
- Heat Wave / Focus Blast
- Focus Blast / U-Turn / Knock Off / Superpower / Taunt
No. 1 -

We nearly lost this as well, which would've been disastrous in the face of such a monster threat dropping right before NDPL (I agree with Runo, fuck OU why now of all times?). Unfortunately, we have issues here. The only way Slowking Galar can stand up to offensive Torn at +2 is with an Assault Vest, so you're immediately locked out of some of its great utility in chilly reception and toxic spikes. Okay, that's not terrible at least. Second, Glowking can only just about do over 50% to offensive with ice beam. Alright, this is still fine, at least it lives two hurricanes at +2 so it can basically sacrifice itself for a 1-1 trade. Thirdly, knock variants not only remove assault vest but also put it in range of +2 hurricane along with rocks chip. ....Now we have a problem. Torn now either nukes with hurricane or switches out, then uses its plethora of opportunities to come in on various threats it beats, clicks nasty plot and beats you next time around. Have fun!
So not a full counter, though at least it's a check. But this is before you consider pursuit support, which can very easily remove Glowking from the equation.
No. 2 -

Hey another reason for this mon to be on every team. But, as I'm going to be saying a lot in this post I think, we got yet more issues. Issue 1, basically every torn will be running heat wave. This is fine on its own, you live a +2 heat wave, hit a leech seed, click protect, you live a second +2 heat wave just barely thanks to leech seed and leftovers and click heavy slam, doing just barely enough for a kill. Issue 2, your counterplay is so linear and forced that torn clicks nasty plot on the turn 2 protect and now you die to the second heat wave. It's a prediction, but not a hard one by any stretch.
Not a counter, let's keep moving
No. 3 -

No preamble here, the issue is obvious. Focus blast just OHKOs even specially defensive variants. Wonderful. Obviously having to rely on focus miss sucks, but it's not a stretch to say that this means standard defensive TTar is out. No, what I'm talking about is Assault Vest or Chople Berry TTar. Yes, I am that desperate for a counter. Rock blast only needs a little chip for an OHKO, or stone edge just nukes it out of the sky, so take your pick of rock STAB.
Aaaand it's u-turn and now you've come in, taken chip, and don't beat it any more.
...
Next!
No. 4 -

Now we're maybe onto something, although we're scraping the barrel a little due to rotom's less than favourable match up into our more common rockers. Rotom heat is able to survive repeated hits from +2 hurricane and heat wave, while only barely being 2HKOed by focus miss, which is better than an OHKO at least? Gives you a chance to do something, and it's less of a stretch to assume that one of two will miss. You can also take advantage of torn's regenerator ability yourself with pain split, leaving the door open for a pain split + wisp/defog + overheat + volt switch/discharge set. The big issue here is that you're dealing with heavy four move slot syndrome, and the second is that a knock torn is very easily able to wear down rotom by forcing it in, removing its boots, then forcing it in later under rocks from the likes of hippowdon and ttar coming in on the overheat aimed at torn. If you're wisp, you're not defog, or if you're wisp and defog you aren't pain split. Any and all of these combinations lose in one way or another, either by being unable to beat many of our common rockers or by the lack of recovery being unable to withstand repeated assaults. But it's better than what we've been through so far at least.
No. 5 -

.....Okay I know I said I was desperate, but dear god. Torn has no immediate way through Diancie, and flyinium-Z sets don't appreciate rocks massively limiting its regenerator. But you have to rely on passive recovery from leftovers, which can be removed by knock variants, massive vulnerability to the good steels in the tier like Aegislash, Steela and Treads, and such pitiful power that you're barely going to be able to do anything to the rest of the tier. But it beats Torn. So that's something I guess.
Honorable mention to calm mind Blissey as well, being used over chansey since it's less knock weak, which technically wins? But is stall only, hates repeated assaults, can be pursuit trapped, loses to taunt variants, and is now complete fodder for any ghost.
Thank you OU. Please ban this.