Aarón Oscuro (アーロン暗い, Oscuro Aarón) is an Arrancar affiliated with the Six Directions of the Ryū Order, where he mainly partners the wild Riki Nagakura and the kind Harumi Kazuki. Formerly a member of Averian's Army of Hollow and Arrancar, Aarón received direct tutelage from Saburo Ryū and Lyon Ryū and is, as a result, quite powerful despite his young age.