A gem that holds a magical girl's power, which its user can use to transform. The gem glows whenever a witch or one of its familiars is nearby.
The soul gem is the power supply of the magical girl and through prolong use the soul gem will slowly darken. But through grief seeds, the darkness can be extracted and allow magical girls to continue to use magic. also In casual clothes soul gems take the form of rings and normally as a highly decorated egg. In battle
soul gems take a different appearance as pieces of their battle gear. Mami has
it as her hair pin, Sayaka has it as her belt buckle, both Kyouko and Madoka
have it as the jewel on their chest, and Homura has it as the jewel on her
gem is literally where Kyubei puts a puella magi’s (magical girl’s) “soul”.
Kyubei’s logic behind removing the soul out of his puella magi’s body is that
they would be more effective fighters. The puella magi benefit from this by
having their pain dulled and lethal injuries healable by magic. As the survival
of their souls are no longer based on the condition of their bodies rather the
condition of their gems. But the drawback from having a puella magi’s soul in a
medium “gem” is that once the soul gem is placed out of range of a puella magi’s
body. It effectively renders the puella magi dead, but puella magi can be
revived by placing the soul gem back into range of her body, which is approximately
a 100 meter radius. In addition the soul gem becomes a puella magi’s weak spot
as it can be destroyed off the puella magi body, instantly killing them. Soul
gems are also the origin of grief seeds. Once a puella magi falls into despair
they become a witch and their soul gem becomes their grief seed. Also Kyubei
can direcly inflict pain onto the puella magi by touching their soul gem such
as the sensation of a spear piecing their stomach. Kyubei does not inflict such
pain under sadistic intentions. But rather as an example why he believes the
soul gem is a good idea to remove the hindering effects of pain in battle.
series Sakaya Miki is the only character to be temporary killed by having her
soul gem moved out of range, hurt by Kyubei’s manipulation of her soul gem, and
soul gem to become a grief seed. But through Sayaka, the other girls learned
about the dark secrets of their soul gems. The other puella magi did not like
Kyubei’s logic and feel like they are already dead and Kyouko dubbed themselves
“zombies”. But having their souls inside a medium such as their gem makes a
puella magi closely related to a “lich” as their soul gem acts like their phylactery.
The soul gem in reality is literally where the Kyubei extracted the puella magi's(magical girl's) "soul". to Kyubei, this was a logical decision to aid in the effectiveness of his puella magi. Once the puella magi's soul was placed into a medium "gem", the girls would be less affect by pain and major injuries can be healed by magic. Effectively making a puella magi into a lich with her soul gem being her phylactery. Kyubei can also inflict pain directly into a puella magi by touching the soul gem such as the sensation of being stabbed by a spear. As a draw back, if the soul gem is displaced from the puella magi about 100 meters away or greater. It would render the owner of the soul gem essentially dead. But can be revived if the soul gem is placed back within the puella magi's range. The Soul gem is also the original source for grief seeds. Once a puella magi has fallen into despair, the soul gem will turn into a grief seed and the puella magi into a witch. In the series Miki Sayaka is the only seen puella magi to have her soul gem placed out of range, had Kyubei directly inflict pain upon and turned into a grief seed. But through Sayaka Miki the other girls learn of the dark secrets of the soul gem. Also the girls did not take a liking to the concept of having their souls removed and dubbed themselves "zombies".