Quirk Singularity

The Quirk Singularity (個性特異点) is a concept postulated by Dr. Kyudai Garaki about the danger posed by Quirks becoming stronger and stronger with each generation.

Overview
About seventy years ago, Dr. Kyudai Garaki presented this theory, according to which, as the generations follow one another, Quirks blend and evolve, producing stronger and more complex Quirks. However, with this increase in power, the Quirks will also become more difficult to control, since the human body doesn't evolve quickly enough to keep up. Eventually, there will come a point when Quirks will become too overpowered and complicated, and no one will be able to control them anymore. This theory was originally called Paranormal Singularity Theory, although over time it would also become known as Quirk Singularity Doomsday Theory.

Back then, no one believed Kyudai's thesis and mocked it, citing that they found it absurd and lacking in evidence, and eventually ignored it. In an era struggling to return an impoverished, conflicted world back to peace, no one believed there was anything to indicate the "collapse of the future". After his theory was rejected and he was ostracized from society as a result, Kyudai went missing.

However, there was one person who took his theory seriously: All For One. With his ability to use so many Quirks, the idea that his body was not able to adapt was a serious issue for him. For this reason, All For One approached Kyudai and offered him his help and patronage to continue his research and investigations in this regard. In appreciation, Kyudai became one of his most loyal allies.

With the passage of time, the Paranormal Singularity Theory began to gain notoriety. The early signs of Kyudai's hypotheses started to appear among the fourth generation of Quirk users, although, even nowadays, the theory is considered fringe thinking reserved for cults, such as Humarise.

During the battle between The Crawler and Number 6, All For One expressed his belief that the two's Quirks had reached the "domain beyond the singularity", as he witnessed their exponential increase in power during their Quirk Awakening.

The evidence of the Quirk Singularity is proven to be positive when Tomura Shigaraki was able to sprout hundreds of fingers from his left hand as the result of his Quirks' mutation, resembling the growth of his Quirks like hair, nails, or skin, showing indication that it will be the result of humanity adapting to the Quirks.

This is further clarified to be the result of his body morphing itself to obtain its optimal shape, with the bloated mass of fingers created due to Tomura's desire for destruction, as well as creating a form that would allow him to defeat and keep the Heroes away from him. However, due to this plan failing, and an increasing mental instability, he was able to further transform his body into a new shape, now in a more defensive state where the fingers cover his entire body, while the memories of his family make up his left fist.