Diagram obviously contains spoilers for story content up to Season 2, Chapter 3 (9/29/2017 Update).

The following image link contains the updated character correlation diagram for season 2, and is originally from the FFBE art book, Final Fantasy Brave Exvius: Art Works II.

Special thanks to /u/Bolbo for providing the original image links to the diagram.

Translated by: /u/Rozaliin

Translated

• Factions, groups, etc.
  
• Character correlations.

Not Translated

• Character names.

→ Character Correlation Diagram ←

→ Season 1 Correlation Diagram ← (Not translated)

I chose not to translate names because of space concerns (things already got tight with what I did translate) and because I don't think it's entirely necessary. If you are particularly curious about a characters name, or want further information as to their relation to someone else, feel free to ask.

Edit: Added the season 1 diagram as well for those who are interested. It was originally posted by /u/saint-ff-. Thanks to /u/LordKaristan for digging it up. Do note that it has not been translated yet.