Cogita mentions in the Enamorous side quest that she’ll let us use Enamorous “for now” stating that she’ll return to her eventually. When asked about it, she states that “you’re not going to live forever”. That’s quite odd considering the PC is a teenager and Cogita looks quite old. Also, Volo mentions that he’ll “keep trying for years, decades, even centuries”. The question is then, are the ancient Celestica people immortal?
Both Volo and Cogita represent one aspect of the human spirit trio. Volo in Latin means “I want” (Azelf). Cogita is a deformation of “cogito” meaning “I think” (Uxie.) Meaning for Mesprit… they’d be named Sentia or Sentio for “I feel”
And there it is…

Sentia -> Cynthia

Cynthia is the third.