Crystal
Crystalia Amaquelin was the princess of the Inhumans, but she was disillusioned with their policies of isolation from normal humans. Leaving them to pursue a life of her own, Crystal encountered Johnny Storm, the Human Torch, whom she began a relationship with. After Johnny left the Fantastic Four, the two married aboard the SHIELD Helicarrier before joining Toxin's resistance. Shortly afterwards, Crystal found that she had developed the ability to manipulate an extremely durable material called Doxium. Crystal later singlehandedly slew Annihilus.
Out of costume
Crystal's primary ability is to harness the four elements: Fire, water, wind, and earth. For dangerous melee combat, she carries a doxium sword. To ensure there is enough doxium to manipulate, Crystal always carries some in a pouch on her belt.