In "The Ice-Maiden", written towards the end of his career, Hans Christian Andersen tells the tale of Rudy, a boy who lost both his parents and goes to live with his uncle. The reader is first introduced to Rudy as he sells toy houses made by his grandfather. Rudy grows up to become a skilled mountain climber and huntsman. He has fallen in love with the miller's daughter, Babette, however the miller does not approve of the union and gives Rudy the impossible task of climbing to the top of a dangerous mountain and bringing back a live baby eaglet. While Babette was off visiting her godmother, she caught the attention of her cousin and flirted with him, which reveals in Rudy a growing jealousy. When Rudy finds the cousin climbing up a tree into Babette's window, Babette is enraged that Rudy is yelling at her cousin and tells him to leave. On his way home, Rudy comes across a beautiful maiden who has appeared in his life before. It's the Ice Maiden, who killed his mother and marked him as her own when he was a baby. He is angry at Babette and soon finds himself kissing the Ice Maiden. Rudy goes back to Babette and begs for her forgiveness. Their wedding day is near and they travel to the godmother's house to be wed at a church nearby. The night after their arrival Babette has an awful dream that she cheats on Rudy with her cousin. One night before the wedding, Babette decides she wants to go to a small island with just enough room for the two of them to dance. As they sit and talk together, Babette notices the boat is slipping away. Rudy dives into the water after it but the Ice Maiden kisses him one last time and he drowns. Babette is left alone on the island crying over the death of her loved one, but nobody can hear her over the storm.

Question: Who killed Rudy's mother?
Answer: The Ice Maiden. 
Alternative answer: ice maiden