The Chimera Ant arc is the longest and one of the most acclaimed story arcs in the Hunter x Hunter manga and anime. It follows a team of hunters, including Gon and Killua, as they investigate and attempt to eradicate the Chimera Ants, a species that reproduces by devouring humans and other creatures, absorbing their genes. The arc is known for its dark themes, complex character development for both humans and ants, and its exploration of the duality of humanity, culminating in a massive invasion of the Chimera Ants’ palace.