On a post-by-post basis, most of your interactions will be either with the denizens of your Dungeon and any neighbouring humans. Should you team up with a Rogue Being, they'll become someone to interact with frequently. Then you'll have occasional (or maybe frequent) contact with other Keepers.

It is up to you to meet up with other Keepers, for they are other players. The purpose and timings of such visits are also up to you. Maybe a trade agreement, or a pact, or a collaboration to attack a common foe, or more likely a battle. I would strongly suggest interacting with other players/Keepers, perhaps forming alliances or enemies early on which you can work through as the RP progresses.

For those who don't want to be a Keeper (or want a second character) can be something we call a Rogue Being. Powerful, although not as mush as a Keeper, they search for a Keeper to serve under. That is another good place for inter-player interaction.