Knights of the Red Branch (KRB) is an Irish terrorist organization.
The Knights of the Red Branch was established by Irish immigrants who left Ireland when it became Tír na nÓg, refugees who fled the island, and those whom were forced out. It's members are full of anger and hatred toward elves because of what happened to them or their country, and turned to terrorism. By 2061 they had been hammered so badly the KRB calmed down quite a bit or more precisely they've gotten less public in their activities.
KRB members in the Boston metroplex will usually attack an elf on sight and will at all times verbally assault an elf they encounter. It's members are really good at provoking others and disciplined enough that others find it hard to provoke them. The upper tier of the organization is well funded and has connections in Boston and elsewhere in the world. Because of their colossal hatred of elves, the KRB has allies and connections to other hateful organizations such as the Black Lodge and the Human Nation, and rumor is that they also are connected to Ordo Maximus.