Long ago, after Kronos first commanded the Sun and Moon but before the rise of Alicorns, there was an age that gave birth to many monsters.
These terrors arose all across the lands. Some came from wild beasts encountering corrupting magic, even those not magical beforehand. A rabbit hopping through a meadow or a bird perched in a forest could at any moment become something dark and twisted. Even sapient beings were not immune to the power of these sinister forces. These monsters took many forms, and while some relied on unusual physical forms to strike fear into others’ hearts, some carried dangerous magical abilities. One such monster was a great ape. Though given sharpened teeth and powerful arms, this creature did not rely solely on its physical form; it had the ability to take the magical powers of others, and use them to increase its own strength.
Among its victims were an ancient clan of unicorns who found that their magic disappeared one day. But these ponies were not aware of the ape, nor of how their magic had been drained. As they had recently discovered Kronos's spell and practiced it, they came to believe that the Sun and the Moon were angered by ponies' irreverence and conceit and had punished them by taking their magic away. So they assembled all the clan together and repented, promising to worship the galactic lights as they deserved. And on that day, their magic was restored.
They believed that the Sun and Moon had blessed them for their devotion and penitence, but in reality, the ape that had claimed their magic had run into trouble while traveling and had plummeted over the edge of a great cliff. Perhaps it had gotten into a fight with another monster. Perhaps it simply made a misstep on unstable terrain. However it happened, its corpse joined many others in the Ravine of Fallen Monsters.
How this ravine became a massive graveyard is a series of stories for another time. But as fallen monsters gathered on the rocky floor—over the course of a few centuries—lingering magic within their remains began to stir and awaken. Many of these monsters were already amalgamations of other beasts, and that magic that bound them rose up once more, bringing together the bodies of monsters from the past and creating life anew.
...oh, the unicorns? Well, they went into hiding and worshipped the Sun and Moon, and had their own history. But that is also a story for another time, although perhaps a time much closer to the present. For now, we turn back to the Ravine, and the resurrections that stirred up the grave.
Thus came the rise of two brothers.