Today we're going to talk about the "Threads of Fate" (tentative) system for Devil Gene R, a concept of which is pictured above. Typically in visual novels the story is told from the perspective of a singular main character, and as such the player is limited to obtaining information for that one point. In DGR character interaction is very important, but not just how Raven, the lead character, interacts with the cast but also how the cast act toward each other.
Everyone has their own story, motivations, and drive, so it just didn't feel right forcing them to conform with one character's tale. So after some thought this "threads" system was thought up; each set of character portraits represent the start of a story. As you can see some portraits are conjoined together, this lets you know which characters will be the focal point for the specified thread you are on. Each black square represents an event sequence where the characters will interact among themselves and often times with others. Each event is tied by a string; red lets you know the events are connected and related, blue implies a crossing of strings which have no relation to each other.
From the diagram you can see that some threads share events, this means a major sequence is coming that can affect the current path you're on. A thread may become entangled with another, making a new path with a broader focus, but the reverse can also happen with threads coming undone.
The primary function of this system is to provide players with some freedom in how the enjoy the story, allowing you to witness events of your favorite characters at your leisure, possibly gaining insight in an interesting way.