Board Thread:Character Discussion/@comment-26241562-20151013033754/@comment-26196542-20151013103655

I think it's more like Buffy in saison 8, the entity called the first was the origin of the evilness. It had the ability to corrupt anyone by appearing as... anyone you meet in your life.

That could explain the presumed casting for the 100th... it could be a way to show all those characters coming back.