The Royal Guard Fairies are the Warrior Fairies that guard and protect the castle on Tir Nan Og and its Queen. They have an Egyptian type clothing theme and have wings made of gold. They appear only in "The Day of Justice".
Although they appear to look like they are at the Winx Fairy form, they are quite skilled at battle and are the strongest of Earth's fairies as they protect the Queen of the Earth Fairies. Since they do not appear again when Nebula took control of Tir Nan Og, it could be that the Royal Guard Fairies remained loyal to Morgana and because of this they may have been imprisoned by Nebula's followers for not supporting Nebula. It is assumed that they have resumed their task of protecting the Queen of Tir Nan Og after the Wizards of the Black Circle were defeated, and that they are now under the orders of Nebula after Morgana handed her crown to her.