The World of D-Gray Man is full of technological devices designed for many purposes. Most of them are the result of the Black Order's research, specifically the scientific section.
Robots are talking, often human-like artificial devices. They are charged with typical tasks by their masters and are able to function by themselves.
- Komlin: A series of robots created by Komui Lee
- 65: A ghost-like robot created by the scientific division
- The Gatekeepers : A series of robots designed to watch the entrance of the European Branch of the Black Order.
- Dolls: The Town of Mater used to create dolls who dance and sing. Lala was one of them.
Some liquids or gases may have particular, or even unexpected effects serving diverse uses.
- The Komuvitan D: A substance originally created by Komui in order to go on without sleep and make people work more. A high dose transforms the subject into an angry zombie, who is eager to spread the Virus.
- Memory Eraser Medicine: A potion used by the Black Order to erase all the memories of those who quit working for the them.
- Knock-out Gas: A potent gas which makes you fall asleep within 3 second of inhaling it.
- Truth Serum: A serum that can be mixed with food. The person who ingests it is forced to reveal information, though its exact efficiency is unknown.
- Komuvitamin DII: A new vitamin drink which is supposed to help perk up those who drink it. It is said to be very efficient but has yet to prove this statement...
- Hair Tonic: Originally created for Bak Chang's birthday. This tonic accelerates hair growth immediately after application. The effect wears off after some time.
- Feline Potion: This potion, when poured on someone, causes the person to meow like a cat, rendering them unable to talk normally. The effect wears off after a short time.
- Rejuvenating Potion: This potion causes one to grow physically younger to their childhood years. The effect wears off after some time.
Prehensile, portable technologies which need to be effectively used by someone.
- Wireless Handcuffs: High-tech handcuffs that restrain the movement of a prisoner so that he remains close to another person or place. If one of the two handcuffs detects that someone is trying to escape or if the two handcuffs end up 20 meters apart each other, it will send a high voltage shock to both handcuffed people/things. A creation of the European Branch's Science Division.
- Talismans: Talismans, seen in several forms (including but not limited to lamps, round shields and heavy duty ballistic shields), are devices that work using unknown mechanisms to form cubed barriers of light that block/contain Akuma. Use is not indefinite; talismans run on battery power that will run out after extended use. They are mainly used by Finders.
- Phones: Finders have been seen carrying ahead of their time corded telephones.
- Innocence Repair Kit: Komui Lee has a lot of items which are used to fix damaged Innocence.
- Radio Earring: A portable radio in the form of earrings made by Bak Chang. It has a stronger signal than the classic radio and is able to communicate as far as inside the Noah's ark.
- Even though the story is set in the late 19th Century, the world of D.Gray-man appears to have developed some technologies that are even more advanced than the ones in real life. These technologies, developed by the Order and the Noah family seem to be hidden from society, which explains why the rest of the world is similar to real life society of the time.
- During the 19th Century, the term "scientist" was often used for alchemists and other magicians. This is why weird things such as Golems and other inventions come from the science section.