Help Need Help Beating a team!

[Kioya]

Hey so I've been having trouble beating my friend his team is this:
Mewtwo: Ability: Pressure, Moveset:Ice Beam, Aura Sphere, Thunder, Psystrike
Groudon Ability: Drought, Moveset:Thunderbolt, EQ, Rest, Frustration
Kyorge: Ability: Drizzle, Moveset: Calm Mind, Ice beam, Scald, Thunder
Rayquaza: Ability: Air Lock, Moveset: EQ, Outrage, Overheat, Extreme Speed
Blissey: Ability I forget, Moveset: Softboiled, Toxic, Minimize
Mew: Ability: Synchronize, Moveset: Aura Sphere, EQ, Super power, Flamethrower
No mega.
Also on a side note if you wanna just build me an OP team I'd appreciate that too. Thanks!​

 

[Scattered mind]

Hey, Kioya!

For this type of casual friendly battle, there is not much opinion people can give you about what to use. Usually, it is easier to comment on teams that follow a certain competitive format, such as VGC OU and Battle Spot. The reason for that is that there is naturally much more to talk about, such as what Pokemon are good and what moves, items, EV's and abilities are the best to use in a given format.

I guess that you can beat that team by using other legendary Pokemon, but it is very vague and general thing to say. The better thing to do, in my opinion, is to learn about EV's IV's and battle strategies. If your opponent doesn't have the knowledge about those things, you will be able to win them fairly easily even with non-legendary Pokemon.

Good Luck

 

[King Arceus]

I think centering your team around Palkia would be a good starting point. It is faster than Kyogre, Groudon, Rayquaza and is immediately able to threaten a supereffective attack. I'd suggest something along the lines of Spatial Rend, Surf, Thunder, and Earth Power. Earth Power is helpful if the weather is sun and Groudon comes in. Latios with a Soul Dew would be another good Pokemon to have on your team. It resists all of Mew's attacks. Dragon Pulse, Psyshock, Grass Knot, Recover provide a way to do large damage to most of your opponents team while also being able to heal itself.

I'll let you figure out the rest of the team since me just building everything wouldn't really teach you anything.