Legendaries are banned as far as I know on the Ranked Battle Spot.
So how on Earth did I end up fighting some with a team of:
-Suikune
-Robot Insect thing with a cannon, guy
-Ugly flying psychic red dragon creature?!
How the hell do I stand a chance against this? Suikune swept my team with Scold, took no damage from Close Combat AND A THUNDERBOLT!!
Did I encounter hacker? And YES, it was Ranked, I am 100% sure, please don't question that.
Only certain legendaries are banned from Ranked Battles. The ones that are banned, iirc, are:
Mewtwo, Mew, Lugia, Ho-oh, Celebi, Groudon, Kyorge, Rayquaza, Jirachi, Deoxys, Palkia, Dialga, Giratina, Shaymin, Darkrai, Arceus, Manaphy, Reshiram, Zekrom, Kyurem, Victini, Genesect, Meloetta, Keldeo, Xerneas, Zygarde, and Yveltal.
Which means that these ones are not banned:
The Kanto bird trio, the Johto beast trio, the Lati twins (without Soul Dew), all four Regis, Cresselia, Heatran, the Musketeers, and I think the Kami trio.
Btw, the robo-insect is Genesect, and I think the red flying psychic dragon thing is Latias.