Jessa was a girl born on the planet Trinium where Willpower shaped how people worked.
Willpower was unique energy that was named based on the mental strain it caused the person using it.
It was an energy that was stored in the mind, and as such manifested its powers by giving everyone unique abilities.
Some could create fire from their hands. Some could move the soil. Some could control metal. Some could transform into something else.
Jessa was born with a rather high affinity with Willpower, and as such, from a young age, she was sure to become one of the most successful Power users in the entirety of Trinium.
However, fate wasn't so kind to this girl who was meant for great things. Jealousy caused people to attack her family in order to kill her.
Many other families pooled their money to hire the entire Assassins guild to kill her family, and more importantly kill her before she manifested her powers.