Mantid society
Mantid assaults on the Serpent's Spine are a terrible thing to experience, both as a defender, and as a mantid. Only the smartest, strongest, or most agile of the mantid survive this encounter, and pandaren defenders are slaughtered outright in terrible numbers.
Mantid survivors make their way back to the great tress, often bearing trophies of their conquests. There, they are welcomed back into the mantid society, and take their place among their civilization according to the level of their deeds. With each cycle the mantid grow stronger. Those who travel beyond the wall are forewarned: any mantid you encounter beyond the wall is a hardened veteran, to be feared and respected.
Mantid are born with little on their mind but a lust for battle. Participation in a swarm is not only a cultural rite of passage - it is the catalyst for their physical maturation. Only those who return from battle can develop from a swarmborn into a fully-aware, individual citizen. Most mantid shed their wings as a rite of passage once they grow strong enough to wield heavy armor and weapons.
The mantid view other races such as pandaren as "lesser creatures", and take pleasure in slaughtering them by the thousand. However, they do not consider these lesser creatures to be entirely without purpose, nor is their defeat the mantid's true aim. Rather, the mantid make use of their enemies' defences to cull the weak from their numbers and hone the skills of the strong. As the mantid say: "Battle is an efficient mentor." The purpose of the cycle is not death. It is knowledge.