The 2nd Supernatural War was Lucifer's second attempt to reenter the realm of Heaven. After taking heavy losses in to his army of dark angels in the 1st war Lucifer experimented with a new breed of being called Demons. The energy needed to create 1 dark angel could fuel the process of creating an entire clan of demons. Lucifer led his remaining dark angels and demons into the war against Michael and his light angels. Lucifer's forces overwhelmed Michael and his light angels as they began tire. Ultimor and his 2 vampiric protégés Solaris and Cho'Bak entered the war to fight alongside Michael and his army and turned the tide of the battle. And for the 2nd time Lucifer's army was forced back into Hell and forbidden access back into Heaven.
Lucifer began the process of creating demons by creating demonic generals first. Anubis was one such demon and he would play a pivotal role in the events proceeding the 2nd Supernatural War.
Lucifer created 4 demonic war clans initially and then created 3 demonic slave clans that were used to as the labor force in Hell and strengthen other demons that were members of the war clans. The slave clans rebelled against Lucifer's forces upon their return to Hell from the 2nd Supernatural War and were able make their exodus out of Hell.