The game keeps track of the relationship between the main characters, as well as between both and the companions / henchmen and NPCs. The results of dual dialogues can effect character traits, and help determine character progression.

It isn't possible to transfer characters between saves. In an aRPG with respawning opponents and simplistic quests that don't influence the character, or vise versa, you can move a character between different saves; that isn't the case with D:OS.