
Who is Jakob Ingold?
Born as Jakob Baker, this character is a citizen of Fontaine, born over 5 centuries ago. His father, Eduardo Baker, was a prominent figure in Fleuve Cendre, the streets nestled deep underground in Fontaine. Perhaps to Jakob, his father is a hero – he protects the people of Fleuve Cendre with a brass tube, defeating dangerous creatures and safeguarding merchants from extortion and harassment by gangs of thieves. He proclaimed: 'Let the sun above belong to them, while Fleuve Cendre is ours.'

But Jakob Ingold's somewhat peaceful childhood was disrupted when the people of Fontaine resolved to regain control of Fleuve Cendre. Eduardo resisted this effort, but it was an unequal struggle. Eduardo and his son Jakob, along with many other residents of Fleuve Cendre, were accused and expelled from Fontaine. On their way to the desert, Eduardo was rescued by his comrades. They fled to the town of Poisson, capturing members of the Hall of Justice and using them as hostages, demanding negotiations.
However, efforts to resolve the conflict peacefully failed, and the Poisson incident erupted. Many people died in the siege of this town, possibly including Eduardo. Jakob and the mayor of Poisson's son, Rene de Petrichor, became orphans, sent to the Narzissenkreuz Institute for nurturing. As you know, here, Jakob, Rene, Alain, and Mary-Ann became close friends, protected by the institute's director, Lyris, and deputy Basil Elton before the appearance of the creature Elynas.
The Tragedy of Elynas
Elynas was once a creature existing for ages, but without a physical form. It wasn't until it received a complete body - perhaps a 'gift' from Rhinedottir - that Elynas truly materialized. With its new form, Elynas explored the world, unaware that its colossal size posed a threat to the people of Teyvat. It appeared in Fontaine about 500 years ago, bringing disaster to the land. The people of Fontaine mobilized their navy to destroy it, with Lady Basil Elton joining the battle and sacrificing herself, while the Narzissenkreuz Institute also sank beneath the water.

From here, the lives of four children took a new turn. Rene and Jakob parted ways with Allain and Mary-Ann to live with Karl Ingold, as arranged by the late Lady Basil. However, in Jakob's mind, Basil's death felt like an 'abandonment', as she left behind a promise to return safely with the institute's director.
A Dark Future
Some time after the tragedy of Elynas, Karl took his two foster sons to Sumeru to explore the ruins of the Khaenri'ah civilization under the guidance of the Nagadjuna Academy. During this journey, young Rene made significant discoveries, paving the way for future scientific research. Notably, Rene also realized that the giant lotus flower Gaokerena within the Harvisptokhm tree - encountered in Genshin Impact 3.6 - shares 'elements' similar to his and Jakob's bodies, but not Karl's.
The distant travels and harsh conditions of the desert quickly deteriorated Jakob's health. Rene feared his close friend wouldn't survive returning to Fontaine, so he used the knowledge of the Abyss he acquired on this journey to save Jakob. Karl vehemently opposed this decision, but Rene secretly carried it out and succeeded. However, it resulted in Jakob no longer needing food or water, making it very challenging for the two children to keep Karl from suspecting.

With the knowledge gained from the Khaenri'ah ruins, Rene discovered the 'Formula of the World' and used it to conclude that Teyvat will collapse. In a few hundred years, all the water on the planet will dry up, followed by a catastrophic deluge covering both land and sky, leaving no remnants of old life, preventing any new civilizations from rising. Jakob wept at this future, but Rene believed he could prevent it. Rene believed that Jakob's unique body would help him survive, and both decided to return to Fontaine to research ways to prevent or aid the people of Fontaine in surviving the catastrophe.
(To be continued)
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