Latios is a staple of overused tier since BW, and in fact proves to be very good in sumo ou, his very offensive typing allows it to threaten many dragon, fighting and poison types in tier, Latios also has a considerable defensive capability to switch in into threats the likes of Keldeo and Charizard y, finally it provides hazard removal support using Defog, which is still helpful for pokemons which need this support.
Latios @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 29 HP / 0 Atk
- Draco Meteor
- Psyschock
- Roost
- Hidden Power [Fire] / Defog
This is the most common set for Latios, powerful Stabs such as Draco meteor and Psyschock are needed to knock out more pokemon as possible, Roost provides a recovery for Latios, in the 4th slot we have Hidden power fire, which is still helpful to lure steel types that usually switch in into draco called Ferrothorn, mega Scizor and Magearna, Defog is an option if the team appreciate hazard removal, other option are Shadow ball, which does a really good damage to Tapu Lele and mega metagross, Surf, is another cool lure move to catch Excadrill, Heatran and Tyranitar switch ins, finally, thunderbolt is another lure move to catch Celeestela, Skarmory, Tapu fini and Mantine switches.
Latios @ Choice Specs
Ability: Levitate
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Hidden Power [Fire]
- Trick / Sleep talk
- Psychic / Psyschock
This is a very cool Latios set, choice specs enables Latios to hit very hard, Draco meteor is a obligatory stab which is not appreciated even by common switch ins, Psychic is able to OHKO a lot of pokemons the likes of Tapu koko, tapu bulu and mega venusuar, Psyshock is a cool variant to cripple Tapu lele and Chansey, 2hkoing them after Stealth rock damage, Hidden power fire is a cool lure move to catch common steel types called mega Scizor, Ferrothorn and Genesect, Trick is a useful move to lock defensive pokemons that usually switch in like celeestela and chansey or setup sweepers like Bisharp into a move, Sleep talk is a interesting option if the team lacks a sleep absorber, with that move, Latios is able to switch into Amoonguss without care about Spore always having the opportunity shooting devastating blows, we have also cool options called Surf, which is really good to hit hard tyranitar, heatran and excadrill, after that, it can use shadow ball, it is a very interesting move that is capable to hit hard tapu lele and mega metagross, finally, we have Thunderbolt, which is able to Ohko and 2hko Mantine and tapu Fini respectively.
Latios @ Choice scarf
Ability: Levitate
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Recover / Hidden Power [Fire]
- Trick
- Psychic
Latios, due to scarf, is capable to revenge kill a lot of pokemons the likes of Greninja, +1 Charizard X, mega alakazam and Pheromosa, Draco meteor, as always, an obligatory stab to revenge kill the aforementioned pokemons, Psychic here to revenge kill tapu koko and tapu bulu is preferred than Psyschock, Recover is a cool move on scarf since it not used as a wallbreaker, and then it can continuously revenge kill threats, Hidden power Fire can catch scarf gene, and does a lot of damage on Ferro and mega Scizor.
Even if Latios is a really strong pokemon, it has many flaws, it don't like pursuit trappers the likes of Bisharp, Tyranitar, mega Metagross and Weavile, fairy types such as Tapus that are very common put a lot of pressure to Latios and the presence of steels the likes of Genesect (especially scarf) put Latios in a bad position in the game, and Magearna, which is extremely bulky can really be annoying for Latios.
After all, Latios is a staple of the ou metagame with its both offensive and defensive capabilities, what are you waiting for? try it out!