Personas are summon-able entities across various SMT/Persona installments... Wild Card users in particular are gifted with being able to carry more than one Persona at a time. The starting limit in Persona 5 is 6, though it can eventually be increased to 16 after meeting certain criteria / levelling up.

Seeing as how 16 is quite a lot... how many would Ren reasonably be allowed to bring along with him?