persona 3 when does mitsuru join

For Shin Megami Tensei: Persona 3 FES on the PlayStation 2, a GameFAQs message board topic titled "5/23 - Akihiko finally recovered, but when is Mitsuru able to fight as well? For Shin Megami Tensei: Persona 3 FES on the PlayStation 2, a GameFAQs message board topic titled "Does Mitsuru *spoilers*".