Players who like Royal Lunatender minions can let them accompany them on their adventures as minions. There are two Lunatender minions: the Prince and the Royal ones. The Prince Lunatender is blue, while the Royal one's skin is gold.
Both minions can be bought or traded from the Market Council using FFXIV Gil, and are random loot from the event. So if the player is unlucky, it's not easy to get them.
The Royal Lunatender is available in the new Treasure Dungeon, Excitatron 6000, which launched with patch 6.05 in January. Players can use the old Kumbhiraskin map to enter the dungeon. This item can be purchased on the market board or acquired in various ways, such as collecting at Thavnair.
However, this is a rare loot from the dungeon, so players may need to farm for a long time to earn it for themselves. But since treasure hunting is one of the best ways to Buy FF14 Gil in Endwalker, it's worth trying this method even with other items as a reward.
Players can also buy the Royal Lunatender minion on the Market Board. Just keep in mind that it will be as expensive as most of the rare loot that can be obtained through a treasure map. While it currently costs around 800,000 FFXIV Gil, it will likely drop over time, similar to most items introduced by Endwalker.