We know the writers has plans for Damien, actually he just got mentiond in the Promeia art tweet that just released, go check it out
But remember how Hugo was introduced in 1.0 and the second time we see him was in 1.6?
I said it multiple times, it's an ongoing story, in a big world with a lot of characters, be patient.
In S1 Chapter 2 we fought Unknown Corruption Complex, which was a Failed Sacrifice, The Exaltists then continues on developing a Successful Sacrifice Syringe under Landon's lead, Landon was Dina's father, Landon was in a different Exaltists group, the Janus Quarter group, then when he was killed by Camille, then the main Exaltists group that is led by Mevorakh/Isolde and Sarah took over his research, and that's how Elixir PO7 came to reality, and then The Exaltists used it on Justin Bringer and he was the first Successful Sacrifices, and Justin Bringer was it's test subject, and in S2 story we see The Exaltists made a lot of Sacrifices because of that, even they made Miasmic Sacrifices, so that's answer it
+ probably the person that Sarah was talking to in phone was Mevorakh/Isolde, Sarah was working under her lead at the end
Anyway, I guess because S1 Chapter 5 story pacing was really rushed made things not clear for some people.
Sarah has connections to HAND and the one of the original Void Hunters, Colonel Vike *the big robot*, so when the story touches on Colonel Vike, highlikly will know more about Sarah.