For Desmond, even angels could fall from his grace, demons become holy, and the universe could turn to scattered ashes. However, the family would still be sacred to him, and even though it happened unexpectedly, he already considered Lilith, his family.
Whether it was blood ties, Desmond's empathy for Lilith's situation, or his admiration for the kind of powerful yet benevolent ruler she had been, according to Nicolai's memories, Desmond felt quite close to Lilith. Calling her his sister wasn't too far-fetched for him.
With all these thoughts running through his head, Desmond experienced a very familiar feeling, something unbelievably similar to what he had been through when he injected himself with Nicolai's blood. Desmond quickly understood that Lilith was trying to transfer or show him memories through blood, a trick that a powerful Bloodmancer like her could pull off.
