Gerhardt Frankenstein

Frankenstein's Monster is Dr. Victor Frankenstein's deceased brother and creation.

History
After dying from some unrevealed cause, his brother sought to revive him with the "perfect heart". He later succeeded in taking it from Fairytale Land, being given to him by Regina, the Evil Queen. However, Dr. Whale, Victor's Storybrooke counterpart said that his brother was still in trouble; and he wished for Regina to send him back home to help in exchange for reviving Daniel. ("The Doctor")