Modified souls (改造魂魄, kaizō konpaku) are artificial souls created by Soul Society researchers some time long ago. They were created to reanimate the dead bodies of humans to act as a formidable fighting force, but this was found unethical and they were ordered to be destroyed. Four modified souls have been introduced in the series thus far, each having been saved from destruction. All have enhanced speed and strength when compared to normal humans, and often special abilities which set them apart from each other. Each typically inhabits a plushie with all of their abilities intact (albeit scaled down to fit their size). Mod souls also possess a personal gigai (義骸), a synthetic human body, that they can use to avoid attention and otherwise regain complete use of their abilities.
