Still covered in the golden scarabs of ages past, Seviper patrol the outskirts of Egypt's great pyramids looking for raiders to bite. The treasures of the pyramids have also been long covered in Seviper venom, yet this venom has lost a great deal of potency after thousands of years; although it can still kill, it does so years after the treasures have been stolen. For this reason, the mysterious deaths to which many pyramid explorers have succumbed over the years were once blamed not on the Seviper, but on a Cofagrigus curse.
A live Seviper's venom is far more potent than one left on an artifact for thousands of years. This venom was often used by deposed Egyptian rulers as a means of suicide, for it was far quicker and less painful than the imaginative methods of execution used on "traitors". In battle, Seviper poison wounds as quickly as the poisons used by the ninja of Fuchsia City, and requires prompt medical attention after the match is completed. Thankfully, in this day and age a pokemon center can prevent virtually all casualties; in ancient Egypt, they were forbidden from the sport of battle for killing too many pokemon, and were used solely as weapons of war.
Ironically, Seviper eat eggs and bugs small enough to crush with their fangs in the wild. Their venom is a weapon of self-defense which originally developed to protect their nests from predators, and its modern potency is a legacy of selective breeding by Egyptians dating back to the dawn of civilization.