Tir Nan Og

Tir Nan Og is the capital of the Earth Fairies and was as well a kingdom in ancient times. All the Major Fairies and other Fairy Queens, like Diana (Queen of the Amazon Fairies)  and Aurora (Queen of the Arctic Fairies), of Earth take orders from the Fairy Queen of Tir Nan Og, except, to some extent, Sibylla who, as Fairy of Justice, has to remain neutral and treat friends and enemies, and Good and Evil people all as being equal and cannot take sides. The fact that even Fairies of Tir Nan Og, under Morgana's direct orders, are not allowed to enter her cave when she has provided shelter to the Wizards of the Black Circle confirms that Tir Nan Og's power has limitations there as it is a sacred place, even if Nebula, due in her thirst for revenge, even proposed to attack and destroy Sibylla's Cave to be able to punish the Wizards, though Morgana was against this.