Petra relocates to the city to pursue a Metropol High School scholarship. That's where she met Lyon. The wealthy and cool young man. As if that wasn't enough in the name of destiny to secure Petra a lifetime contract with Lyon. Lyon's future wife.
LGfM 280
...
Petra didn't budge one bit.
The threat that the Demon King placed on him would not be able to affect Petra at this time because Petra's main focus was to annihilate all the Demon Kings on the plane and save Ludi.
For a moment, Petra closed her eyes to detect the presence of the Demon King hiding in one of the objects in the cockpit space. Until Petra's focus was on one of the levers on the left side of the pilot screen monitor. Then, lock it with a golden-white fire element.
"The toy you used is no longer useful enough. Do you think we didn't learn anything from that incident? When your anger peaked when Cherries killed Jason? We know your strongest element is fire." The Demon King's words were punctuated with mocking laughter.
Instead, Petra just smiled and laughed softly.