is an artificial soul modified by a Soul Society operation known as "Project: Spearhead
" to inhabit a dead body and use his special powers to help the Shinigami fight Hollows, Kon's special power is in his leg muscles. His name is a short for Kaizō Konpaku (
or Modified soul or Mod-soul for short
). Ichigo uses him to transform into his Shinigami form, leaving him in charge of his body the way normal Shinigami use artificial souls to look after their gigais. When not serving this purpose, Kon usually inhabits a lion plushy.
Kon primarily serves as a comedic foil in the series; when not inhabiting Ichigo's body, his normal plushy body is treated with little respect and much disdain, sometimes bordering on abuse.
Kon is quite perverted and is preoccupied by sex much of the time. He will often try to take advantage of his plushy body to get girls to hug him to their chests. Kon is especially attracted to girls with large breasts, which makes Orihime the center of many of his fantasies. In the manga he is also seen using Ichigo's body to gratify himself while fantasizing about Orihime and Rukia
Kon's redeeming quality, which allows Ichigo and Rukia to see him as someone worth saving, is his views on the sanctity of life. Because he spent many years in the form of a pill, fearful that one day he would be discovered and disposed of, Kon has developed a moral stance that prevents him from killing anything. He will also risk his own life in order to save even the lowliest of creatures and is angered to see people who belittle their creations and dispose of them off-hand.
The Mod-souls were the product of a Soul Society project called "Spearhead". The goal of the said project was to modify artificial souls so that they could be inserted into dead human bodies and turn them into foot soldiers or cannon fodder in the war against the Hollows. Each Mod-soul had a unique superpower meant to help it fight.
Kon was one of the last Mod-souls ever created. Shortly after his creation the project was deemed inhumane by Soul Society and was shut down. All of the existing mod-souls were to be terminated. Kon, however, made a lucky escape, along with some other Mod-soul pills, and wound up in the storage room of the Urahara Shop, inside a Soul Candy dispenser. Urahara placed the tainted dispenser in a box designated as "poor merchandise" and had intended to dispose of it but for some reason never did.