Celeste, like Flora, did not have it easy. But she could hold on due to the difference in skill.
Flora was still a beginner in combat, but Celeste was one of the Luminarii— the strongest soldiers of the Avians. And backed by her gifted bloodline, there may be a single handful of Avians who are stronger than her. Her father was one. And anyone else, if any, was not there in Clarus.
She also uses a glaive like Flora, but their weapons had their own differences. There were no runes on Celeste's blade, nor did it glow with iridescent light. But it was shaped like a raging flame with the blade on one side and the flames on the other.
There was a gemstone with a scarlet hue on the guard collar— a catalyst. Flora was not yet trained enough to get one. Since a reusable catalyst was extremely rare and hard to craft and keep stable— only the trained Luminariis and the regent himself carries it around.