All of you are idiots. TPC (whose definitions are the only ones that matter) officially classify them as follows:
Legendary: Articuno, Zapdos, Moltres, Mewtwo, Raikou, Entei, Suicune, Lugia, Ho-Oh, Regirock, Regice, Registeel, Latias, Latios, Kyogre, Groudon, Rayquaza, Uxie, Mesprit, Azelf, Dialga, Palkia, Heatran, Regigigas, Giratina, Cresselia, Cobalion, Terrakion, Virizion, Tornadus, Thundurus, Reshiram, Zekrom, Landorus, Kyurem, Xerneas, Yveltal, Zygarde, Type: Null, Silvally, Tapu Koko, Tapu Lele, Tapu Bulu, Tapu Fini, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma
Mythical: Mew, Celebi, Jirachi, Deoxys, Phione, Manaphy, Darkrai, Shaymin, Arceus, Victini, Keldeo, Meloetta, Genesect, Diancie, Hoopa, Volcanion, Magearna, Marshadow, Zeraora, Meltan, Melmetal
Ultra Beast: Nihilego, Buzzwole, Pheromosa, Xurkitree, Celesteela, Kartana, Guzzlord, Poipole, Naganadel, Stakataka, Blacephalon
Lore doesn’t matter. Those are their official classifications. End of story
