Proserpina

Proserpina (プロセルピナ) is a Magic God of Roman Mythology and a member of the true Gremlin, first mentioned in Shinyaku Toaru Majutsu no Index Volume 13.

Etymology
is the Roman goddess of the Underworld, her Greek equivalent being. A daughter of the agriculture goddess Ceres, she was abducted by Pluto, god of the Underworld, to be his wife. Her distraught mother searched desperately for her daughter, letting the crops wither away in her grief. Jupiter eventually had Pluto release Proserpina but because she ate the food of the dead, she couldn't completely return to the world of the living. As a result, she spends six months with her mother and six months with her husband, resulting in the changing seasons.

Appearance
Proserpina is a young woman in a black Western mourning dress with a hood and veil of the same color.

Personality
Proserpina's full personality isn't known, but she has displayed signs of personality traits typical of Magic Gods.

Magic God Invasion Arc
At some point around the time of the incident instigated by the High Priest, Proserpina encountered Kamisato Kakeru and was 'exiled' by his World Rejecter.

Salome Arc
Proserpina remains exiled, but her likeliness was used in a bluff by Kihara Yuiitsu while fighting Kamijou Touma, Salome and Misaka Mikoto, making use of Sample Shoggoth and an attenuated St. Germain virus to make imitations of the Magic Gods and their magic, to make them think she could draw out the Magic Gods and their power after stealing World Rejecter from Kamisato Kakeru.

48 Hours to Restore Order Arc
On December 9th, after Kamisato Kakeru himself fell victim to the World Rejecter's power, Proserpina was among the Magic Gods who beat him up shortly after his arrival in the 'new world', though they didn't kill him. At that point, she and the rest of Gremlin were content to stay in the isolated world, but were keen for the new arrival to leave as soon as possible. A destructive struggle between Gremlin occurred when Nephthys and Niang-Niang decided to protect the boy against Proserpina and the Magic Gods who sought to continue the punishment. During the battle, she used her magic to block the sun and create a planet-wide artificial ice age.

Abilities
Being a Magic God, Proserpina is powerful enough to risk destroying the world with her mere presence unless precautionary measures are taken. Even weakened by Aleister's spell, she is still capable of destroying the world.

Among the spells Proserpina has is a divine punishment spell based on the legend of her abduction to the underworld, where her angry mother made it so that spring would never come until she retrieved her daughter. The spell covers the sun and fills the world with -60 degree snow and ice; a planetary-scale artificial ice age.

Character Art Design
According to Haimura, there weren't any particular details focused on in the designs of Proserpina and the Magic Gods whose appearances were shown for the first time through Yuiitsu's fabrications, given their lack of mention in the story.