Two wands with cores coming from the same magical creature, referred to as "brothers", cannot be forced to duel against one another. Should two such wands ever come in the way of one another, a rare connection is formed, called Priori Incantatem. When the connection is formed, the wands battle to merge a golden orb into the other's shaft; the one that succeeds to force the orb in the other is the winning wand. Because of its rarity, most wizards never learn that such a connection is possible - this is the first law of Priori Incantatem.

After two brother wands connect through means of Priori Incantatem, both wands come to know one another and may react towards each other without the consent of their owners, or the winning wand only reacts towards the losing wand - this is the second law of Priori Incantatem. Also, under special conditions it is possible for one wand to recognise its "brother's" master, even when a different wand is used. For example, during the Battle of the Seven Potters, Harry's wand recognized Voldemort and spurted "golden flames" at him, even though Voldemort was using the wand of Lucius Malfoy.