When Theresa talks about playing hide-go-seek with her brother in "simpler times" before a bandit raid ended that life forever. Made more poignant by her explaining her long life means everyone and everything she cared for is dead and gone. After five centuries it's still her fondest memory.
Theresa's confession to Gabriel. She admits that she was responsible for the deaths of Lucien's family, Lucien, Rose, and every slave Lucien worked to death. All so she could gain the Spire. And the worst part about it, when she finally had it in her possession the truth about why it was destroyed in the first place made her burst into tears for the first time in two centuries. The terrible things she'd done for the greater good had only made things worse. Their deaths had been meaningless.
The moment Fergus finally finds his wife. He had no illusions that she was alive but the relief to have found her body and to be reunited with her is all that mattered to him. When he's mortally wounded saving Gabriels life he's happy to die by her side. All while knowing he didn't run this time.
Gabriels farewell to Seren. They both knows she's going to die and she bravely charges off to meet death head on.
