Herrscher of the Corruption

"After being sealed away within this box, I have no clue about what has happened outside and I don't know how much time has passed. The hatred in my heart only keeps growing. After thousands years, I was imprisoned in darkness. But then one day, that priestess opened the box. Yes, in that priestess' heart I found a similar resentment. Hatred. Anger. A perfect tool for my revenge upon humankind."

- Herrscher of the Erosion in Sakura Samsara.

"Unforgivable! You opposed me all this time, but what can you do with the mere strength of a human? Let me say it once more! You are powerless before me! Watch closely and despair! You shall never be reunited with this girl again!"

- Herrscher of the Erosion before devouring Yae Sakura.

"You should be thanking for making the foolish delusions of the villagers become reality! To be devoured by a God you love and believe in, isn't that a blessing?!"

- Erosion to Kallen.

Herrscher of the Erosion, also known as 12th Herrscher, Hellmaru, Ruler of the Erosion, 12th Ruler or self-called as Yakujin or God of Disaster, is the overraching antagonist of the popular 2018 manga Guns Girl School Dayz, a side-story of the iOS/Android game Guns Girl Z and Honkai Impact 3. Herrscher of the Void is introduced as the main antagonist of the School Dayz manga, the overarching antagonist of Honkai Impact 3rd - Purple Kite's Tales, the central antagonist of Honkai Impact 3rd - The Secret of God Keys and the main antagonist of Honkai Impact 3rd - Gratitude Arc. Due to her machinations in the Old World and starting the Second Apocalypse, she is considered to be one of the most important antagonists of the franchise alongside her successor Herrscher of the Void.

12th Herrscher had the ability to project her own consciousness onto any object and control it freely. In reality, this Herrscher was actually a self-aware lethal virus which infected everybody and turned all life forms into zombies. Not only that, but they was also able to control machines, launching nuclear missiles and destroyed a part of the old world. Professor Mei had to seal they into the Purple Box before they managed to destroy the rest of human civilization. 49,000 years later after God Kiana reseted the world, they were still sealed inside of the Purple Box until it fell into Schicksal's hand, causing the Black Death in Europe during the Medieval Era, killing 1/3 of the population of the world. After witnessing the inhumane experimentation of Schicksal using Crystal Disillusionment, Kallen stole the purple box and ran away to Yae Village and later got fatally wounded. Yae Sakura later unwittingly opened the box, releasing Higyokumaru and all her stored hate all over the past time and possessed Sakura, turning her into a large fox beast that was later defeated and sealed by Kallen.

In-game, the Nine-Tailed Fox shows up as a boss in the Simulation World.

Official Description
12th Herrscher had the ability to project her own consciousness onto any object and control it freely. In reality, this Herrscher was actually a self-aware lethal virus which was coloured black, which infected everybody and turned them into zombies. Not only that, but she was also able to control machines, launching nuclear missiles and destroyed a part of the old world. Professor Mei had to seal her into the purple box before she could destroy the rest of human civilization.

The purple box later fell into Schicksal's hand, causing the Black Death. Eleanor Schariac injected a fragment of this Herrscher onto herself, becoming a large spider beast and later got defeated by Kallen and Otto. After witnessing the inhumane experimentation of Schicksal using Crystal Disillusionment, Kallen stole the purple box and ran away to Yae Village and later got fatally wounded. Yae Sakura later unwittingly opened the box, releasing Hellmary and all her stored hatred all over the past time and possessed Sakura, turning her into a large fox beast that was later defeated and sealed by Kallen.

Higyokumaru currently resides in the Stimgata dimension after the events of the Sakura Samsara.

Guns Girl Z - Old World
Herrscher of the Erosion, or also known as the 12th Herrscher, was a sentient self-aware virus that was fused with Honkai energy and gained free will to act and think by herself, which infected humans and animals and turned them into zombies. After they gained freedom to think the disease quickly considered herself to be superior and saw all humans as food and her plaything.

The virus then infected a little innocent girl and used her as a host to spread one of mankind's most deadly plagues that killed 90,000,000 people in a few months. When the innocent girl was discovered to be the host of the disease, the now Herrscher of the Erosion used her energy to bring the army straight to her, resulting in the innocent girl being tortured by scientists to discover a cure for the plague and then executed in cold-blood.

Once her host was destroyed, the Herrscher quickly left her body and infected all civilians in the North Asia, turning half of China's population into zombies and hacked into America and Asia's nuclear bases, launching nuclear missiles and destroying half of the world, killing billions more just to create her own Plague Kingdom. Professor Mei then sealed the disease inside of a Purple Box, where they would be kept sealed for 49,500 years.

Medieval Era
49,500 years later after God Kiana/Sirin reseted the world, the Herrscher of the Erosion continued locked inside of the Purple Box until one day in 1490, the organization Shicksal found the box and began to experiment on it. Once they were free, Herrscher of the Erosion evolved and infected half of Europe with the Bubonic plague, starting the Black Death and the Second Apocalypse, wiping out 1/3 of the world's population. When the main heroine discovered her lover, Otto Apocalypse (who was still a good guy back then and became the story's Big Bad thanks to Herrscher of the Erosion), was perfoming human experiments to fix Herrscher's cruelty, she stole the Purple Box and fled from Europe and went to Asia.

In Asia, Kellan was severely injured by Shicksal's hunters and was rescued by the innocent Yae Sakura. Herrscher proceeds to self-call herself as Yakujin, God of Disaster and infects Yae's body, controlling her and her emotions. As the years passed, Herrscher cursed the village with plagues and scarcity of food and water, leading the villagers to adopt cruel methods to save their village; sacrificing children to the Gods. Inside of her body, Herrscher forced her to kill children in sacrificial rituals that were supposedly to be sacrifices to "please the Gods" when in fact it was only giving more power to Herrscher of the Erosion.

One night, Herrscher of the Erosion takes over Yae's body and kidnaps a young girl from the village. In the forest, they tied the girl in a tree and killed a bear that was just passing by before turning the animal into a Honkai creature and gave the defenseless girl to the Honkai to be devoured alive. One day later, Herrscher dispatches the creature to attack the village, killing dozens of men, women and children to force the villagers to sacrifice even more children for their safety. When the ritual was interrupted by Kallen who considered their ceremony heartless, Herrscher transformed herself into a giant ghost fox and devoured the child before crushing her mother with her paws. When Kallen asked the creature why they were doing all of this (to Yae who was being controlled by the Honkai), Herrscher simply said villagers should be thankful for being devoured by a God and then states she is going to destroy everything Yae and Kallen loves the most, making her way towards the village to kill the rest of the villagers.

After devouring and killing all the villagers, Herrscher burned the village to the ground. After a long fight, Herrscher of the Erosion defeats Kallen and forces Yae (who is currently watching inside of her subconscious) to watch they killing her lover but Yae breaks out of her mind control and commits suicide to prevent herself from killing her loved one. Herrscher returns to her Fox monster form and devours Sakura right in front of Kallen to show how much she is powerless before a "God".

They then fights Kallen and is sealed for more 500 years inside of Kallen's stigmata.

Mordern Era
In the modern era, when Theresa's stigamata causes her to lose her consciouness, Bronya concluded something happened with her stigamata which was originally from Kallen (the deceased lover of both Otto Apocalypse and Yae Sakura 500 years ago). To investigate what happened, Raiden Mei is sent to Theresa's stigamata world where she meets a fallen Past!Kallen on the middle of a burning village that turned out to be Yae's village after Herrscher of the Erosion destroyed it.

Theresa then awakes inside of the stigamata world and meets Yae Sakura from that world. Knowing they finally had a chance to return to the real world, Erosion took the form of Yae's father and dispatched a horde of Honkai monsters to attack the village and devour the civilians alive to blame Theresa for luring the Honkai creatures to their peaceful village. In a reunion, Erosion (as Sakura's father) proposes sacrificing more children to protect their villages from the Gods' wrath but when Theresa invaded the room to rise her opnion about killing children, Erosion threw a rock at Sakura as a way to punish her from bringing such young girl to the village.

Leaving of the room, Erosion discovered Theresa was Sakura's last hope and vowed to destroy her so they can be free again. They later had a chat with Sakura to taunt her about all the victims they killed 500 years ago, including remembering her of when she killed hundreds of children in the name of a God that didn't even exist when was in fact none other than Erosion themselves. At night, Erosion sent their women to capture a sleeping Theresa to sacrifice her. When she resisted, Erosion ordered to cut her both of her feet so she couldn't escape.

At the sacrificial ritual, Erosion revealed their plans to sacrifice Theresa so they can take over Theresa's body in the real world and escape from the stigamata world. When Yae Sakura refused to kill her, Herrscher of the Erosion invaded her mind and forced her to remember when she killed her own sister in a similar sacrificial ritual, while in her mind, Erosion controlled her body and impaled Theresa with her katana before disposing of her body. As Yae began to dissolve, Erosion embraces her they love her and now are going to drag her to an eternal nightmare.

In the real world, Erosion takes control of Theresa's body and happily laughs for finally being revived after500 years. They proceeded to attack Kiana and Bronya to celebrate their revival but was quickly knocked down by Theresa's will. With their defeat, Erosion returned to the stigamata and faced Mei in combat. During the combat, Erosion caught the sight of Theresa and Sakura and returned to their original goal of destroying their minds and taking over Theresa's body but a revived Kallen Kaslana appeared before them after 500 years dead. Without wasting time, Kallen began to seal the Herrscher again but before the ritual could success Erosion invaded Kallen's mind and searched for hatred inside of her memories.

There, they found the source of her hatred, Otto Apocalypse and used his form to corrupt her as one last resource to avoid being sealed, however, Theresa showed affection and love for Otto, refusing to fall for Erosion's temptation. With nothing more to do, Erosion accepts her fate of being sealed again for the time being.

Power and Abilities

 * Self-aware Lethal Virus: can infect all life forms and turn them into zombies and mindless monsters. They were also able to control machines and hack into military codes, having access to any kind of virtual world, including the Internet itself.
 * Herrscher Authority: they can control zombies and beasts unless there is another Herrscher controlling them.
 * Honkai Creation: Like other Herrschers, they are also able to create Honkai monsters by killing animals and reviving them Hybrid-monsters.

Trivia

 * Higyokumaru and Sakura both share a fox-like motif, which is why Herrscher of the Erosion took the form a Nine-Tailed Fox as her primary form once they arrived in Japan.
 * In her new form, Erosion becomes a Kitsune. Kitsune is the Japanese word for the fox. Foxes are a common subject of Japanese folklore; in English, kitsune refers to them in this context. Stories depict them as intelligent beings and as possessing paranormal abilities that increase with their age and wisdom. According to Yōkai folklore, all foxes have the ability to shapeshift into human form. While some folktales speak of kitsune employing this ability to trick others—as foxes in folklore often do—other stories portray them as faithful guardians, friends, lovers, and wives. Foxes and humans lived close together in ancient Japan; this companionship gave rise to legends about the creatures. Kitsune have become closely associated with Inari, a Shinto kami or spirit, and serve as its messengers. This role has reinforced the fox's supernatural significance. The more tails a kitsune has—they may have as many as nine—the older, wiser, and more powerful it is. Because of their potential power and influence, some people make sacrifices to them as to a deity. Conversely foxes were often seen as "witch animals", especially during the superstitious Edo period (1603–1867), and were goblins who could not be trusted (similar to some badgers and cats).