🔎The clues①
Kurea was able to enter the "field" where the Precures were fighting.(Story from Episodes 22)

🔎The clues②
It's known that Cure Eclair was once at the CUREtto Detective Agency with Luluka Moria. (Story from Episode 21)
So it seems highly likely that Luluka Moria knows Cure Eclair...
Luluka talks with Shiruku Ieiri normally, but when she talks to Kurea Howa, she seems flustered.
Could it be that Luluka knows Kurea? (Story from Episodes 22 and 23)

🔎The clues③
Shushutan, who also appeared on this site. Kurea is wearing a scrunchie that's same color as Shushutan.
The true identity of this scrunchie was Shushutan, who had been watching over Kurea.
In fact, because she was with the companion fairy friend Shushutan, Kurea was able to enter the "field" where the Precures were fighting.