The Overseer Music Box is a device used by Warfare Overseers of the Abbey of the Everyman, which, when activated, prevents the use of any supernatural abilities within range, and can send out a sound-wave barrier to keep Corvo Attano away. Daud and his assassins are also susceptible to its effects.
As such, Corvo is required to use his ranged and melee weaponry to combat Overseers who use them. The music box can also harm Corvo by firing Windblast-like waves that push him backward, deal heavy damage and negate magical powers.
Corvo first discovers the device in the workshop located in the Backyard of the Office of the High Overseer, where it is described in a note written by High Artificer Bartholomew and called "Holger's Device". According to the studies of the Abbey of the Everyman, the box produces "mathematically pure" notes, which act on the theory that there are hidden waves throughout the natural world.
In an audiograph recorded by the High Artificer, the concern is raised over whether or not the mechanism and its effects are themselves magic. However, this issue is not addressed by any other members of the Abbey.
Overseers carrying this music box can be especially deadly. In addition to having their faces shielded by masks, those who carry the box can use it to protect themselves from strikes to the chest. The box's great range, ability to block damage, and Corvo's hampered ability to flee without his powers make music box Overseers priority targets during combat.
A good strategy to kill an Overseer with a music box is to fire an incendiary bolt at his legs, as Overseers move slowly when carrying a music box and are easy targets. Grenades, explosive bullets, and sleep darts are also effective. They are vulnerable from the rear so attacking them from behind is a good tactic. If taking the low chaos approach, always make sure to get rid of Overseers with music boxes first. Their music can stop Corvo mid-Blink and can cancel Possession. Dark Vision will also be canceled or disabled when within range.
- Even though it is implied that Bone Charms, which usually emit some warmth, turn cold and useless close when in the vicinity of the music, Corvo's charms will continue to work normally.
- Two City Watch Officers can be overheard in the Estate District discussing a rumor that a group of Overseers declared a woman a witch because she lost her voice just as Overseers passed by with a music box.
- Music boxes can also break glass and cause whale oil tanks to explode.
- Overseers occasionally play the music box even when not alerted. This does no damage but still negates supernatural abilities when close by.
- One concept image shows what appears to be a stilt-less Tallboy wielding a music box instead of an Overseer.
Enemies in Dishonored