Erin just continued trembling while trying to think of more reasons to use to try to convince Serenity to let her live.
Serenity smirked. "All out of reasons? Too bad. But then again, even if you had convinced me not to end your life, there are still plenty of others here that would've taken you out instead and I would've let them. You see, my sister likely wanted to end you just for what you caused Spencer to go through..but it would've been worse by your attempt to kill me. Aaron would've killed you for trying to kill me. Spencer's sister would've wanted to end you for previous stated reasons..and well...there's a list. So you've made quite a few enemies here. " She reached and yanked her dagger out from Erin's shoulder.
"So...I never stood a chance." Erin realized.
"Exactly." She dragged her finger along the blade of her dagger, causing it to extend to a full size sword. She then aimed the blade right at Erin's heart. There was a fire in Serenity's eyes and the blade ignited. "Goodbye Erin Strauss...and good riddance." With all the grace of the princess she is, she lifted the sword in her hand, her hardened yet fiery gaze on Erin. "In the name of the moon and earth, I, Princess Serenity pass judgement on you for your crimes against the royal families of the moon, earth and mercury. Your life is forfeit as is any chance of rebirth." She then swung her arm back and brought it forward, stepping forward so that the blade sliced Erin's body in half. The moment it finished passing through, Erin's body burst into flames and her normal starseed was dusted.