I think that with any such multiple characters, it would be important that those characters operate in different<em>spheres,</em>e.g. Only one power-hungry character, only one character with an intense desire to collect archeoarcana, only one character with spymaster ambitions, one character active in the underworld or slave trade or mercantile enterprise or grand strategy...  If you have a character that ticks all three of those boxes, build something else or tweak to correct the overlap.<br/><br/>A<em>little</em>bit of casual overlap would be fine - two characters with arcane magic? Sure.  Two combat-types? No problem - as long as they are<em>differently motivated</em>and<em>differently employed.</em>I feel like that would probably go a long way to prevent self-dealing, and in those occasions where self-dealing<em>could</em>occur, great big GM flags to ensure that player agency isn't violating the spirit of the game - but that would require any additional active characters being put under a much more restrictive lens, which puts more pressure on Phantom.<br/><br/>Sometimes, player agency has to take a backseat to the game - elsewise there would be no GMs.  Or referees in sports.  Or laws.