Order 77 was an event that took place several years after The Battle for Berk and Equestria.
Order 66 was an event at the start of the New Jedi Order which the double agent clones of the Republic turned against their Jedi commanders and terminated them, bringing about the destruction of the Jedi Order. This was carried out by Nightmare Moon and King Sombra sneaking troopers that worked for them into the regular clone army
After the construction of the New Jedi Temple, after having revealed themselves to the Jedi that the Nightmare Family still lived Nightmare Moon issued Order 77. The hidden clone troopers across the galaxy turned on the Jedi and began killing them, with numerous Jedi perishing on battlefields on many different worlds. Meanwhile, fallen Jedi Knight Brian Griffin, who had become the Sith Lord Darth Manacore, marched on the Jedi Temple with a group of clones and killed the Jedi within it. However, while several Jedi were killed more Jedi survived this Order, and then a small team attacked the Nightmares' base and completely destroyed it, and even eradicated their Stormtrooper army. While Nightmare Moon lost her left wing to King Solar Flare, while Sombra suffered a serious slash to his face. But during their years of hiding they created The Nightmare Empire.
- This Order did cause the death of Several Jedi but it didn't work out as well as Order 66.