After getting a firm decision from Max, Fye and Max approached Chleo and explained to the red soul that the Vectis had cruelly taken.
They also told Chleo that they plan to unite the red soul in the urn into the red soul currently residing in Chleo's body.
Chleo was shocked at first because she didn't know that the red half soul had possessed her. He hadn't even felt anything all this time and had absolutely no idea when the red soul had slipped into his body.
The half-red soul that managed to enter Chleo has fused with Chleo's current soul so that Chleo's mental state and red soul gradually recover and no longer feel traumatized. But it's different from the red soul that's half again.
This red soul lost half of its soul due to being slashed by Vectis, then locked and held in an urn created by Vectis to ensure this red soul would not be able to escape again.