The White Fang: a street gang of faunus and humans to rival any racist gang out there. They started out as a faunus rights group, trying to spread the message of peace and unity. Once they realized their message was being ignored, they used another method of ending segregation. Their method: violence-ranging from knife fights to brutal methods of torture.
The Hunters: a gang that started in the prisons but became infamous in the streets. A group of humans who are against the idea of unity between faunus and humans. Very dispicable humans; besides their rivalry with the White Fang, the Hunters have indeed killed many innocent faunas-including children- ranging from lynch mobs to a massacre at a bowling alley in the 1980s.
Both factions got their start in different places. The White Fang was formed in Menagerie by Leo Belladonna-the father of Ghira Belladonna. They eventually moved to Vale since it has the largest faunus population outside of Menagerie; as well as the biggest city of the four kingdoms.
The Hunters were formed in Atlas by François Gelè-the father of Jauque Schnee- as a far right anti-faunus group. Once the Hunters learned the White Fang moved to Vale, they moved too. When segregation ended all across Remnant, the Hunters didn't take it well. To spread their message of hate, they would torture and murder any faunus and humans who associated with the faunus.
The majority of those incidents happened in Vale, as Atlas became a military power which meant gangs would not be tolerated any longer. Since both gangs have claimed Vale as home, Vale has become the very center of a gang war. No one is safe; if you hear the gunfire there's a good chance you're dead.
Both factions have adopted extreme methods of torture and killing. The White Fang specialize in dismemberment, while the Hunters specialize in lynching.
Vale's murder count has gone up to ten a day-both gang and civilian deaths-and that number will continue to rise until a solution is found. Considering this war has gone on for five decades, that solution might not be found anytime soon.