A new legendary Pokémon in Pokémon Go is always a welcome sight, giving competitive players a new powerful choice to consider using in their roster. They might try to figure out if it’s going to be a good choice to use in PvE raids or PvP, namely the Master League. For Therian Form Tornadus, you’re probably trying to compare to Tornadus’ Incarnate Form. These two Pokémon are different, and you want to consider the unique moveset and stats that Tornadus (Therian) has available to it.
Tornadus (Therian) is a Flying-type Pokémon. It will be weak to Electric, Ice, and Rock-type moves, but it is resistant to Bug, Fighting, Grass, and Ground-type moves. If you’re going to face off against Tornadus (Therian), you want to use an Electric and Rock-type Pokémon.
Rather than gaining additional attack power, Tornadus (Therian) has a higher defensive stat, making it a more durable Pokémon. For PvP, Tornadus (Therian) has a maximum CP of 3,215, an attack of 199, a defense of 161, and a stamina of 160. When using it in PvE raids, Tornadus (Therian) has an attack of 238, a defense of 189, and a stamina of 188.
While in the Therian form, Tornadus loses 23 points of attack power, but it regains that in defenses. If you want a more sturdy Flying-type Pokémon in your roster for the Master League, Tornadus (Therian) is a solid bet. It doesn’t have a dual typing like Lugia or Ho-Oh, though. It will tackle Groudon, Swampert, and Garchop. But it overall doesn’t compete too well in the Master League unless it’s used in specific circumstances. It will lose to Thundurus (Therian), Zekrom, Zapdos, Melmetal, Raikou, and several others. There are multiple Electric-type legendary Pokémon regularly used in the Master League. You’re better off sticking with Tornadus (Incarnate).
The real turning point for Tornadus (Therian) is its moveset, which is a huge letdown. The best moves it can learn is gust for its fast move, and then psychic and hurricane for its charged moves. Gust does a decent amount of damage. However, because psychic and hurricane require so much energy, Tornadus (Therian) needs a fast move that produces more energy or lower-energy charged moves. Both psychic and hurricane are above 50, crippling this Pokémon in most PvP battles.
Overall, Tornadus (Therian) will be a poor addition to your Pokémon roster. Like any legendary Pokémon, it’ll be powerful, and you can use it in several situations. But it’s extremely held back by its moveset, and the altered stats don’t help it. You’re better off avoiding Tornadus (Therian) in any form of Battle League competition, and you should probably stick to Tornadus (Incarnate).