She does die, but not by Nightingale.
Wendy manage to rescue Nightingale, but Cara poisoned her as retaliation.
Nightingale used that chance to wound Cara and escaped with the poisoned Wendy, hoping to get to Border Town and have Nana heals her.
An oddball witch, Lightning, decided to left the group during the confusion and went with Nightingale
Wendy can control wind and Lightning can fly (can't carry heavy loads)
During this time, Nana went through her demon's bite day, and the change was so weak Nightingale who was watching didn't notice it happened and only realized it has passed when Roland pointed out a new day has come.
After this, Wendy made an oath of allegiance to Roland and asked for permission to return to the camp one more time.
She want to try to convince more sisters to come to Border Town, or if not that at least tell them about using magic = weaker or no demon bite
On the Witches side,
Cara kept on the search for Holy Mountain, following a cryptic passage she found in some book
Well, they kinda saw the city mentioned
But turns out it's just a mirage of the actual city, long abandoned
The Witches run into Demons, and the latter slaughtered many of them, Cara included
Left in despair from not finding the Holy Mountain (and the only lead, Cara, is dead) and the death of most of their sister, the survivors, scattered by the initial attack, return to the camp.
Of the 42 of them at the start of the journey, only 7 survived.
Leaves, a combat witch who control plant, was voted to be the leader when it was confirmed Cara is dead.
After pondering for a moment, Leaves decided that she want them to head to Border Town, since the Holy Mountain Cara seek is not real.
Just in case, Leaves will go in alone first, with the others hiding nearby, in case Nightingale's story is fake.
If it's true, then Border Town is exactly the Holy Mountain they were looking for, and so their journey will ends.
And that's how Cara is dead and Roland get 7 witches, all by doing nothing and going on his business as usual.