Legendary Pokemon are notoriously powerful and are some of the best Pokemon in Pokemon GO.
Pokemon GO's meta is drastically different from the main series' meta, but the fact remains that most legendary Pokemon are competent enough to be usable. However, the best Pokemon are the ones that can actively shape the meta itself.
Note: This article is subjective and reflects the opinion of the writer.
What are the 5 best Legendary Pokemon in Pokemon GO?
#5 - Rayquaza
The soaring serpent Pokemon of the skies, Rayquaza is a powerhouse of terrifying proportions. It boasts a massive attack stat and a threateningly high max CP, giving it all the power it needs to wipe out opponents.
Rayquaza is even more difficult to overcome when one considers its access to Dragon Tail and Outrage, both of which are high DPS moves that only fall short against Steel and Fairy-types.
However, with quite a few glaring weaknesses (Fairy, Rock, Dragon, and a 4x weakness to Ice), Rayquaza can go down shockingly fast, especially in the recent meta, with Abomasnow and Giratina (Altered) dominating the scene.
#4 - Cresselia
Cresselia is a defensive option that still contributes to damage with its piercing Psychic attacks.
Cresselia has decent bulk, letting players switch it in when their main attacker is on the ropes. It also has access to the back-breaking Future Sight attack, which does a significant amount of damage to make up for its larger charge requirements. For coverage, Cresselia can use Grass Knot to supplement a team's weaknesses.
Unfortunately, Psychic isn't exactly a great defensive typing, so Cresselia ends up taking more damage than it wants despite its bulky stats.
#3 - Registeel
Registeel has been a constant presence in the Pokemon GO competitive scene for quite a while.
The Pokemon not only has an obscenely high defense stat, but it's also the superbly tanky Steel-type, which resists 10 entire types and is heavily resistant to Poison (immune in the main games).
It goes for a solid EPS (Energy Per Second) move, then hits hard with Hyper Beam. The higher energy cost doesn't mean much for a Pokemon that can outlast the vast majority of enemies.
#2 - Giratina (Altered)
Both of Giratina's forms are vicious in their own right, but its Altered form is undoubtedly the more potent of the two.
The Altered form boasts a higher defensive stat between the two, which may seem like an awkward choice. However, it ends up having a dangerously high DPS, despite its lower attack stat and less powerful moves.
By having a higher defense, it can last through the risky Pokemon that hold type advantage over Giratina. Giratina also resists 6 types and is heavily resistant to 2 others.
#1 - Mewtwo
Mewtwo is a supremely powerful Psychic-type Pokemon that decimates almost any opponent given the chance.
Possessing one of the highest max CPs in the entirety of Pokemon GO, Mewtwo can shred just about any target with the devastating Psystrike.
However, Mewtwo is also an incredibly adaptable Pokemon. It can learn charge Moves from six other types than its own.
Even Ghost and Dark-type Pokemon have to worry when going up against a Mewtwo lest the mono-Psychic-type Pokemon have Focus Blast or Shadow Ball up its sleeve.