It was Discord that did the most damage, there were not many of their species, and while Frosted was a cool and calm force, much unlike his brethren, many ponies still associated them, in fact ponies gained a distaste for anything different or strange, and Freezeria was filled with different and strange. His kingdom was filled with the odd and the misfit, bicorns, moth ponies, hybrids and all manner of curiosity. Most without the common pony feature of a cutie mark that was bestowed upon the primary pony races. He tried to remain quietly to the side for a time, not hidden, but not openly public either, it did little to help though. Finally when the Shadowlands, Empire of the bat ponies withdrew and shut themselves off from Equestria completely, their Empress angered over what had been done to Luna, Frosted decided he needed to do the same.
It was not as if he was angry with Celestia for what she did to her sister as the bat Ponies were. He understood that it hurt her greatly and that the Nightmare Moon persona of her sister had left her little choice. The simple fact was that it was no longer safe for him to keep Freezeria open. His creatures were consistently attacked abroad. He feared their safety and the stability of his kingdom.
So he withdrew and all in Equestria forgot him and his frozen land, save perhaps Celestia. Freezeria hidden in a bubble of time and ice away from the greater pony lands.
But in long time, word came to him that Luna was returned from her exile on the moon, restored to her former self. The bat ponies returned to her side, the Shadowlands once more revealed. That was enough and indeed he was decided, he would join the other leaders on the public stage once more. But ever cautious, he took time and logic to plan. Sending creatures out to investigate third modern Equestria. Freezeria had after all been in isolation a very long time and was still populated with the unusual, moreover, he worried Celestia would hold a grudge.
It was through this careful time taking that he had surprise visitors. Discord and Celestia much to his shock. His once villainous brethren was now on the side of good, and the sun princess reassuring him that she held no grudge, she understood he withdrew to protect his creatures. This, it turned out, was exactly what he needed. He brought his kingdom back out into the open and joined the other leaders and old ones on a world stage. Standing together as they once had before.
Base by Pepsi-Dreaming