Tree Diagram

The best super-computer in the world, according to the best renowned scientists in Academy City. This computer was loaded into the satellite, Orihime 1, to monitor many aspects of the city such as weather patterns and security.

Another use of this computer is to aid researchers with their experiments. This consent, on the other hand, is very difficult to acquire since the Academy City's Board of Directors are the only ones who are able to permit access to Tree Diagram. One permitted use of Tree Diagram was for the 'Sisters' Project, to calculate a way to achieve Level 6. According to the results taken from this computer, by taking the best Level 5 Power User (Accelerator), it was calculated that if about 128 Level 5 psychics were defeated by Accelerator, he would achieve Level 6. However, Academy City only had six other level 5 psychics, so by using 20000 Level 3 clones of Misaka Mikoto, they expected the same result.

During Touma's fight with Index (while being possessed by Johann's Pen), Index accidentally directs a Dragon Breath's attack to space and destroys the Orihime 1 satellite, destroying Tree Diagram permanently. Meanwhile, Academy City covers up this incident by announcing that Tree Diagram can't be contacted for an indefinite period.