Twenty-two unsuspecting, relatively ordinary people notice that a strange new app has mysteriously appeared on their phones. Yet with a simple tap in curiosity, their lives are changed forever...
There's a little devil in us all. From the depths of one's psyche manifests a Persona. For the Arcana, these take the form of traditional youkai in order to aid and protect their hosts when needed most. More often than not, a Persona reflects the host's inner personality too, whether in appearance or behavior or both.
Abilities and strengths vary immensely: attack, defense, support, physicality, elementalism, stealth, buffs, debuffs, and so on. However, Persona are limited to knowing 4 special moves outside of ordinary (inter)actions. Note: any attacks made that are not one of your four special moves will not be considered damage dealing to a Shadow or Goetic.
After the first time a Persona has manifested itself, it can be summoned again with a flourish of the Apperator and a calling of its name. From there, it's unnecessary to vocally announce attacks; simply thinking of the attack is enough for the Persona to perform it.
Because a Persona is part of a person's psyche, extreme psychological duress can weaken the link between Persona and host. This bond is then vulnerable to infection, in which case the wild Persona will break away as a Shadow youkai and must be conquered in order to return to its rightful Arcana. If not, its only goal will be to kill its former host, then anyone the host held dear, then simply anyone at all.