It all started in Transylvania. The Silverarrows' ancestors were the Transylvanian Saxons who displaced the werewolves' ancestors from their motherland. That was why the two groups were against each other. The fight for motherland had taken different shapes in the subsequent centuries. Then there were personal emotions which colored the globe red.
Actually Silverarrows were the ancestors of Vald the Impaler or Dracula or the first of the vampires or father of vampires or god of vampires. But Silverarrows had no supernatural powers and they did not believe in the lame movie Underworld.
After the ancestors of Silverarrows invaded the werewolves' motherland Transylvania in the early 1200s, the werewolves escaped to Eastern Carpathian Mountain Range and lived in its valleys and hills. There they settled. They showed their loyalty to the Romanian empire and became royalty in that area. The Silverarrows were also no less. They also became royalty of their area. Though both the groups or communities were loyal to Romanian throne, they remained secret enemies of each other. They fought hand in hand, shoulder to shoulder in many battles against the Ottoman Empire, but they fought a lot of secret battles that were unknown to history. These things were taught to Silverarrows and perhaps to the werewolves through their oral traditions.
Werewolves were supernatural beings with powers as such: shapeshifting ability, supernatural communication power, super sensing power, incredible healing power, they're impossibly fast and they live for centuries.
Whereas Silverarrows were normal human beings. Unmatched against their supremely powerful enemies.