Emma Frost

Origin
Emma Frost was create when Thalia Phoenix was born. Emma was Thalia's darkness, although she originally didn't have her own form and only lived inside of Thalia. After a while, Emma grew stronger, and was able to use her telekinesis to steal another person's body. With being part of Thalia, Emma was able to go through The Underground whenever she pleased. One day when Thalia was still young and discovering her powers, Emma came and put an electronic curse on her. This curse caused Thalia's lighting to go dark and cause pain to herself. When Emma revealed herself to Thalia's father, Aster Phoenix and grandfather, Ash Phoenix, she offered to fix Thalia in exchange for Ash's soul. Ash agreed and gave his soul to Emma. Emma kept it in a small box, and let Thalia free of her curse. Emma then left The Underground, and went to the World of the Colossus, a legendary world filled with monsters of ultimate power. With Ash's soul in her possession, the monsters feared Emma and would obey her every command. Emma has an ultimate goal though, to capture the vessel of a girl named Mono, a legendary princess in the Collosus World. The only issue is that Emma must be whole in order to fully gain the power that Mono's vessel has. Emma decides to wait until Thalia is older and stronger in order to kill her and take Thalia's power for herself. She decides to join H.Y.D.R.A. as a way to battle with Thalia, with revealing her ultimate plan quite yet.

Cursed Journey to Freedom
After the battle against the Phoenix Force, Thalia returns home to the Underground only to find into Emma waiting for her. Emma reveals her past to Thalia and who she is. She warns Thalia that she will kill Thalia one day and to be ready to fight. Emma then leaves The Underground to return to Magnusaur.