I think Cerberus is spelled all kinds of ways... but yes, familiars and summons are skills. In the Sorrow games, you summoned them with particular souls and they hung around fighting with you until your MP ran out. But in Curse of Darkness, the Innocent Devil summons had their own health bar. They were summoned into being, then acted as a partner until dismissed or their health ran out. In that case, they revert to a glowy orb spirit state unable to do anything until you collected hearts. I'm working with both explanations for familiars here.
Okay, all but one posted, so I moved ahead past the initial ambush. Death has scattered the group. There are four locations that you can end up in. Some players can choose where to go, some have been assigned for plot reasons.
-All of the Heirs and Yoko remain in the Outer Courtyard. The Heirs' starting items are behind the sealed doors; the seal breaks when the person who gets the equipment inside touches the door.
-Genya has been transported to the southern part of the rooftop. I would like this group to remain smaller, as he's going up to investigate the Lofty Throne area. Even if you try to find a way back to the group, it'll take longer from this location. It's not a major area, so there isn't a rooftop boss in the plans (yet).
-Cadence has been transported to Twilight Garden (from her SU), on the northern side of the main castle structure. This group will have a relatively easy time meeting back up with the Outer Courtyard group, but there are a few things that can be investigated in the Garden as well.
-Masquerade, Belladonna, and Death went to the Infernal Dungeon (from John's SU). On the B1 map, it's the prison-like area on the left, in the bottom room with two symbols in it.
-Anyone else can choose where they end up, with the options being the Outer Courtyard, Rooftop, or Twilight Garden.
On the various areas, I'll have certain rooms and features decided on, and describe these as they're approached and investigated. Otherwise, you're free to describe what a particular room looks like or build off of what I or another player posts.