Whose wand is the 'brother' to Harry's wand (same phoenix feather)?

Voldemort’s wand is the “brother” to Harry’s because both contain tail feathers from the same phoenix—Fawkes, Dumbledore’s bird. Ollivander explains in Philosopher’s Stone that the phoenix gave only two feathers; one chose Harry, the other chose Tom Riddle. Because of this twin core, their wands won’t properly fight each other, producing the Priori Incantatem effect in Goblet of Fire: a golden connection forms and Voldemort’s wand regurgitates echoes of his recent victims. This bond even drives plot: Voldemort later seeks a different wand (first Lucius’s, then the Elder Wand) to overcome the twin-core limitation. Memory tip: Fawkes links the foes—two feathers, two fatal enemies.