The greatest Doll engineer of the modern time owning the title of National treasure. Cero's caretaker and the creator of Belle who always calls him "Father". His real name is Ein Ronberg which caused him a lot of trouble in the past. Ein was former illusionist so he took his stage name "Rein Helmer" as main. He was one of the lead researchers in the "Efa resurrecting project" but retired after a few failures and falling in love with his colledge, dollmaker Rooth.