Something that the surprisingly volatile Persona community can unanimously agree on is Koromaru's status as Persona 3's best companion character. Sure, some might prefer Yukari's company to Mitsuru's when ascending the more dangerous levels of Tartarus, and Junpei will always have his defenders. But at the end of the day, each temporarily inhabits party space reserved for our beloved kunai-wielding Shiba Inu, something we predict will still be the case when Reload arrives on 2nd February.
Koromaru offers the strength and loyalty of his magnificent kind, defending the party as fiercely as he did his former master. With the ability to summon his own Persona, Cerberus, the only thing missing is Persona 3 Portable's female protagonist, who got Koromaru as a Social Link instead of Yuko Nishiwaki. We still wouldn't be surprised if that were dangled as DLC somewhere down the line, but we'll have to wait and see on that last.
