The Iron Doll is a mini-boss in Melody of Darkness. He, along with three others, must be fought to access Drachaos' chamber. There is no order in which to fight them.
In the first form, the Iron Doll is a very heavily armored warrior. He slowly walks toward the player. He can dash, and swipe his sword. He has 200 HP in this form.
The Iron Doll's armor falls off, revealing him to be a skinny Slogra-like creature. He hops around, shooting crescent discs and swiping with his sword. He has 800 HP in this form, and his theme for both forms is Resonance of Malevolent Souls.