Despite being in just a handful of episodes, Milah left quite an impression on me. She is Rumplestiltskin’s’ first wife. Killian Jone’s first true love, Baelfire’s mother, and naturally the paternal grandmother of Henry Mills.
Her early life isn’t very happy. While she enjoys being a mother, she hated being the wife of a coward. So eventually she leaves Rumple and Baelfire for a “better life.”
Which was being the semi-wife of Killian Jones. She does seem to be a good fit for a life at sea. She makes a deal with Rumple to spare their lives when he finds out she’s alive and happy.
But he’s angry at her for leaving Baelfire, and takes her heart out and crushes it when she screams at the Dark One that she never loved him.
In a tragic sense of irony, the two meet in the Underworld. She agrees to help her ex-husband when their goal is the same, the rescue of Killian Jones from Hades.
It seems the two former spouses had worked their anger out.
But when Rumple gets forced into a contract by Hades, he is “forced” to get rid of Milah by throwing her into the river of lost souls, which is a cruel fate. She deserved better than that.