Kaminari

Kaminari is the main character of Black Wings, Kaminari and a famous figure in the recent history of the other world (the setting of My Impossible Soulmate and Save the Princess, among other stories). Not much is known about her personal history other than the fact that she was a outsider both back in her home and down on the ground, as well as her fame by the time Chiaki wound up in the other world.

Early life
Kaminari was born to the royal family of Toria, the floating kingdom of the skyfolk. Unwilling to sacrifice her due to her black wings but too ashamed to reveal her to the public, her parents claimed she was stillborn and raised her in secret. The first sixteen years of her life were thus spent inside the castle basement, cut off from the outside world. One day, she heard lots of commotion outside of the castle and stepped outside to see a black-winged baby like her being "banished" from the kingdom. She dove off the kingdom and saved the baby (who would later be named Nagisa), but having never used her wings before, she couldn't fly, so she did her best to slow their descent. While both Kaminari and Nagisa survived the impact, Kaminari had held Nagisa so tightly that her wings had broken, and thus neither of them were able to return to their homeland.

Time on the ground
Kaminari and Nagisa landed in a farming village under her kingdom where the "banished" had ended up and were buried. She saw the graves the locals had dug for the "banished" infants and felt horrible and swore she would save someone for each grave and eventually return to end the awful practice that had condemned too many to an untimely death. A human family, moved by Kaminari's resolve, offered to raise Nagisa, and Kaminari set off on a journey to help those in need. Along the way, she was joined by Hokori, Aneko, and Rei. At one point, Hokori nearly betrayed Kaminari, believing that he could use her to get into Toria to obtain one of the seven legendary blades he aimed to collect. However, he eventually repented and became one of Kaminari's closest allies. Both Hokori and Aneko eventually fell in love with Kaminari, though it is unknown which one (if not both) of them ultimately got together with her. Kaminari learned the stories of various past Lilim along the way, most importantly Genten, a black-winged skyfolk hero from centuries prior who had advised a corrupt king and attempted to stop him in his tracks before being betrayed and made into a scapegoat. By doing her part in ending the banishment ritual and presumably bringing down the Torian monarchy, Kaminari fulfilled Genten's destiny, becoming an honorary Lilim.

After the defeat of Eligos
During her time in the other world, Chiaki gradually learned about Kaminari and her team's exploits. After returning to her home world, Chiaki eventually adapted these stories into a manga titled Black Wings, Kaminari.