Not sure if i'm too late to submit but
Firium Z
Tornadus-Therian @ Firium Z
Ability: Regenerator
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Hurricane
- Knock Off
- Heat Wave
- Defog
Inferno Overdrive has a 93.8% chance to OHKO that Shift Gear Magearna that thinks it can set up on you, also does a ton to other Magearna sets.(Knock off+ Heat Wave + Inferno Overdrive will KO standard assault Vest Magearna, which is nice). Heat wave is also helpful for dealing with Mega Scizor(81.3% chance to ko 248 hp/244 spdef impish after rocks with heat wave,) Ferrothorn(with Inferno Overdrive OHKO'ing, to nobody's surprise), Celesteela, and inferno overdrive has an 81.3% chance to OHKO the rare alolan Ninetales. It can also hit Kartana(and grasses like serp and offensive bulu if weakened) more reliably than hurricane without needing to use your Z move.
Firium Z

Tornadus-Therian @ Firium Z
Ability: Regenerator
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Hurricane
- Knock Off
- Heat Wave
- Defog
Inferno Overdrive has a 93.8% chance to OHKO that Shift Gear Magearna that thinks it can set up on you, also does a ton to other Magearna sets.(Knock off+ Heat Wave + Inferno Overdrive will KO standard assault Vest Magearna, which is nice). Heat wave is also helpful for dealing with Mega Scizor(81.3% chance to ko 248 hp/244 spdef impish after rocks with heat wave,) Ferrothorn(with Inferno Overdrive OHKO'ing, to nobody's surprise), Celesteela, and inferno overdrive has an 81.3% chance to OHKO the rare alolan Ninetales. It can also hit Kartana(and grasses like serp and offensive bulu if weakened) more reliably than hurricane without needing to use your Z move.
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 0 HP / 4 SpD Magearna: 300-354 (99.6 - 117.6%) -- 93.8% chance to OHKO
0- Atk Tornadus-Therian Knock Off (97.5 BP) vs. 248 HP / 0 Def Magearna: 28-33 (7.7 - 9%) -- possibly the worst move ever
252 SpA Tornadus-Therian Heat Wave vs. 248 HP / 224+ SpD Magearna: 124-146 (34.1 - 40.2%) -- guaranteed 3HKO
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 248 HP / 224+ SpD Magearna: 226-268 (62.2 - 73.8%) -- guaranteed 2HKO
252 SpA Tornadus-Therian Heat Wave vs. 248 HP / 244 SpD Scizor-Mega: 292-348 (85.1 - 101.4%) -- 81.3% chance to OHKO after Stealth Rock
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 252 HP / 232+ SpD Ferrothorn: 448-528 (127.2 - 150%) -- guaranteed OHKO
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 248 HP / 0 SpD Ninetales-Alola: 340-400 (97.4 - 114.6%) -- 81.3% chance to OHKO
0- Atk Tornadus-Therian Knock Off (97.5 BP) vs. 248 HP / 0 Def Magearna: 28-33 (7.7 - 9%) -- possibly the worst move ever
252 SpA Tornadus-Therian Heat Wave vs. 248 HP / 224+ SpD Magearna: 124-146 (34.1 - 40.2%) -- guaranteed 3HKO
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 248 HP / 224+ SpD Magearna: 226-268 (62.2 - 73.8%) -- guaranteed 2HKO
252 SpA Tornadus-Therian Heat Wave vs. 248 HP / 244 SpD Scizor-Mega: 292-348 (85.1 - 101.4%) -- 81.3% chance to OHKO after Stealth Rock
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 252 HP / 232+ SpD Ferrothorn: 448-528 (127.2 - 150%) -- guaranteed OHKO
252 SpA Tornadus-Therian Inferno Overdrive (175 BP) vs. 248 HP / 0 SpD Ninetales-Alola: 340-400 (97.4 - 114.6%) -- 81.3% chance to OHKO