In the rule “Personality Traits” add the following text:

A Wizard’s Dominant Trait is that Wizard’s single Personality Trait with a value of at least 3 and higher than any of that Wizard’s other Personality Traits. If a Wizard does not have a single Personality Trait whose value meets the preceeding criteria, that Wizard does not have a Dominant Trait.

In the rule “Spells” add a subrule named “Simpatico” and give it the following text:

Effect: All Wizards in this Duel with the same Dominant Trait as the Wizard casting this spell, including this Wizard, gain 1 Star. If no other Wizards have the same Dominant Trait as the Wizard casting this Spell, this Wizard gains 3 Stars instead of 1. This spell has no effect if the Wizard casting it has no Dominant Trait.
Traits: The Dominant Trait, if any, of the Wizard casting this Spell