
Originally Posted by
Absimiliard
tl;dr:
Venat condemned her own race to extinction based on lots of supposition and the word of some dude from the future.
WoL benefits from the Blessing of Light, a spell that only she (Venat) could cast while having part of Azem's soul colour.
Spoil about Azem, WoL & Hythlodaeus:
Azem's soul was split into 14 with The Source and its 13 reflections, WoL was the reincarnation of Azem's soul fragment from The Source. Ardbert is the reincarnation of Azem's soul fragment from the First Reflection.
Hythlodaeus always says: "My not so new friend" with his gift that Emet-Selch also has, he saw in the soul of the WoL a tiny part of Azem's soul, he says this sentence because he knows somewhere that it is his friend from the old world.
So it's not just anyone to her. It's a person with his mark that can only come from the future, since she doesn't remember casting it on WoL. So it's likely for her that somewhere it was herself from the future who sent it. So it's not just a random guy.
Unless you skip some dialogue, she didn't believe blindly, but she investigated with the WoL until she got the proof with Meteion's revelations at the end of the Elpis dungeon, driven by her curiosity like anyone who has been Azem.