Cure Prism is another case of Odd Name Out...which is actually perfect on its own. Among the first otherworldly and blue leader Cure, the first permanent male Cure, the first (legally) adult Cure, and the first one-year-old Cure, Mashiro sticks out like a sore thumb.
Word of God states that the costumes and colors of the Cures in this season are based on times of day. In order, there's Prism (dawn), Sky (daytime), Wing (sunset), and Butterfly (dusk). Cure Majesty being the mid season team member to join, who has a purple theme color, would then fill in the night theme to complete a full day cycle.
Ever wonder why this season keeps Breaking Old Trends left, right and center? There's a certain phrase, "The sky's the limit", allowing the creators to experiment with different kinds of Cures instead of sticking to the usual formula.
Butterflies are the adult stage in a caterpillar's life cycle, so it's fitting that Cure Butterfly is the oldest of her group and the first legally adult main Cure.
Also, Ageha specifically states that she is eighteen years old in her debut episode. Which episode has her debut as Cure Butterfly? Episode 18!
While it seemed out of place and been memed that Cure Peach was skipped and later came in at episode 26. The main reason Cure Peach was featured was a nod to Peach Airlines.
In the crossover movie, the four main Cures are teamed up with select guest cameo Cures. Ageha/Butterfly happens to be teamed up with Lala/Milky, Yukari/Macaron, and Asumi/Earth. Earth/Asumi is physically an adult, Macaron/Yukari is close to adulthood compared to other Cures (being seventeen), and while Milky/Lala isn't an adult in terms of Earth years, she is considered an adult on her home planet. Ageha's team are literally adults to a degree!
As revealed in episode 22, Underg Energy is deadly to humans, making them unsuitable hosts. The question of how Battamonda knew this is horrifying enough, but—remember his gambit in episode 15? Had it succeeded, the resulting Underg corruption would've killed everyone in Sky Land.
Episodes 44 and 47 bring terrifying implications of the whole existence of Pretty Cure in Skyland being due to a Stable Time Loop; Cure Noble created the Chroniclun after she grows old, intending to Fling a Light into the Future. She then creates Elle to deal with a sudden spike in Undergu Energy, giving her most of her remaining power. However, if Skearhead had been successful in eliminating Cure Majesty *or* the Cures had not had the Majestic Chroniclun when the Empress faced them, there's every chance Cure Noble wouldn't have come to exist, and potentially Skyland as it is would not exist, trampled by Skearhead and those he manipulated, meaning there would be no way to ever stop his thirst for conquest...
When Skearhead filed the emergence of Cure Majesty into his mind palace, it wasn't just to develop a strategy against her—he'd almost certainly marked her down as a backup vessel.
