Dr. John Seward
Having faked the extermination of Lucy by the Vampire hunters John hid her away, sending their child to a friend to safeguard Darcy from realizing her vampiric heritage, and to escape being hunted by what should have been her family.
Despite locking Darcy up in what amounts to a prison, Dr. Seward does deeply care for and love his child. The time he spends traveling the country as a vampire hunter is not meant to keep him away from Darcy, but is due to his frantic dedication to cure his child of vampirism. He watched Lucy’s world crumble around her and does not want to ever see his child loose her world as well. Keeping her locked away from others was the only way he could conceive of to buy himself and her time to work on a cure and to give her at least the semblance of a normal life.
Once Dr. Seward learns that his daughter vanished in the middle of an escape of The Pride he will not leave a stone unturned to get his beloved child back.