The aqua-winged Fel Beast was by far the most feared monstrosity to emerge from the Dusklands. This was not merely on account of its humongous size, razor-sharp fangs, and powerful sorcery that could summon raging storms at a moment's notice. No, the beast's most terrifying aspect was its ability to not only understand the speech of humans, but read their minds and lay traps they were certain to fall victim to. And that's precisely why they could understand the advantage of invading the "realm beyond the wall."
During Dark Horizon Event.