D is a pill created by Dr. Aris specifically for DA-5 and herself. It is a small, gray pill that enhances the strength, speed, and overall ability of the user when it is consumed. The secondary purpose of the pill is that if an emergency arises, it lets Kranz or Dr. Aris absorb the power of the members of DA-5 with greater efficiency so that they can become powerful enough to overcome or escape any potential foe.
When analyzing the pill, Frankenstein discovered a side-effect that causes the users' cells to deteriorate, shortening their life-spans. Frankenstein has since replicated D and removed its side-effects. He initially created two different types of pills based on the original D. One of those pills did not have any of the harmful side-effects, but gave a much smaller power increase of about 30% of the original. The other of Frankenstein's prototype D pills was consumed by Dr. Aris and was responsible for her deteriorated state that caused partial memory loss. It was meant to replicate the effects of D except with a 200% increase in power and a strawberry flavour, though it had the side effect of an imminent death. The new D were created separately for Tao and Takeo, and if someone else consumed it, their body would break down.
After being allowed more time to research about D and the bodies of Tao and Takeo, Frankenstein gives the duo another pill called T-2 which is named after them. T-2 is a lot more stable and effective than the previous pill Frankenstein created. These pills are also suited for Tao and Takeo only.