Jacqueline

Jack is a giant killer, who participated at a war against them. He defeated all of giants, except one. He tried to defeat the last one, but the latter killed him.

Before the Curse
Jack was a human, who fight the giants in a terrible war, defeating all of them except one. When he launched his attack on the Giant's castle, at the top of the beanstalk, he failed and he was killed by his ennemy. ("Tallahassee")

After the Curse
At the base of the beanstalk, Killian tells Mulan, Aurora, Emma and Snow that it's the last beanstalk in all the lands and the Giant at the top is the last of his kind because of a man named Jack. Later, in the Giant's castle, Emma and Hook discovered Jack's skeleton, in the treasure room. Emma was astonished when she saw Jack's sword, saying it is a toothpick.

However, when the Giant attacked them, Emma proceeded to collect Jack's sword from his skeleton's hand. Emma turned to face the giant, sword in hand, as it continued to walk towards her, at the right moment, Emma sliced the sword through the air, chopping through the tripwire as she did so. The cage on the ceiling tumbled down, landing on the giant, entrapping him beneath it. ("Tallahassee")