Sar-Ilam did not travel through the Void...
"...Belket participated in the War of the Ancients. He is a brave warrior and became one of the first angels to recognize the fight against the faceless as unholy. Exiled for his dissent, he went into seclusion and began to study dark magic in order to better understand how Sar-Ilam was able to travel through the Void..."
2.
Necromancy is the magic of Ashan, allowing one to control the "order" of the cycle of life and death; it has nothing to do with the Void, and Sandro simply sought to completely destroy this cycle.
Source: http://ru.ashan.wikia.com/wiki/Белкет
Added 11 hours 47 minutes ago
And does Inferno already have the Archangel Sara? - if not, I'll try to come up with something.
http://ru.ashan.wikia.com/wiki/Сара
Блистает там воздушностью прогалин.
Но между кедров, полных тишиной,
Расщелина по склону ниспадала.
О, никогда под бледною луной
Так пышен не был тот уют лесной...