Durin, the great abyssal dragon who's corpse litters Dragonspine (hence the namesake). Who's heart still beats centuries after his defeat. A creation of Rhinedottir that "attacked" Mondstadt during the events of the cataclysm. Who's fight with Dvalin alongside Barbatos (Venti, the anemo archon) left Dvalin poisoned for 500 years leaving him vulnerable to influence from the abyss order. The threat that is Durin continues to loom over Dragonspine and Mondstadt as even though he lays dismembered strewn across the mountain blood flows from his still beating heart. One day he may restore himself and "attack" once again. The presence of his corpse makes Dragonspine a harsher place as his blood alone has altered the life on the mountain and attracts unwanted attention. He's was an abyssal monster who's appearance worsened an on going crisis.

Similarly over in Fontaine there was the abyssal dragon Elyans. Another creation by Rhinedottir that also layed waste to Fontaine during the cataclysm. What's interesting about Elyans compared to his brother Durin is that we get to learn more about and communicate with him. From both this and his offsprings (the Melusines) we learn that those of the abyss like Durin, Elyans, and even the Melusines see the world differently. Differently enough that Melusines have historically had a hard time integrating with Fontainan society. Creatures like rifthounds (another creation by Rhinedottir (on gawd why she make those, they annoying, got the whole party on their knees even if they haven't seen the field)) appear to them like dogs and act accordingly (This is in a Fontaine world quest). So for Elyans all those years ago when he finally got to travel Teyvat and meet the life that littered the world, he'd eventually come to realize that his traveling brought suffering. His existence alone harmed others where he desired companionship resulting in him seeking death so he couldn't hurt anyone.

Durin was similar to his brother Elyans, Like Elyans he perceived the world differently, but unlike him never came to the realization that what he perceived differed to reality. At the same time when he appeared in Mondstadt all those years ago he apparently was poisoned, ill from consuming subject two (A prior failed iterations of Albedo, another creation of Rhinedottir). In what little we do get from him he speaks of his "attacking" of Mondstadt and following death. He describes the events as being drawn in by the soulful songs (probably from Venti, or not potentially due to the perception difference. Maybe the songs were the screams of the people during the cataclysm. I mean Venti only awoke because of Durin's attack, not the cataclysm (this is a lie, he was summoned for Khaenri'ah)), singing along the people, and finally dancing in the sky with "a dragon as beauteous as a jewel". All this as quoted from the Dragonspine Spear. His view of events clearly don't match reality but they still allow you to understand him. There's a desire for companionship thats present with him, something he doesn't live long enough to obtain. The skyward blade, pride, and spine all give a more accurate telling of events; his appearance in Mondstadt, his fight with Dvalin, and the tearing of his throat by Dvalin. (this was helpful a hoyolab post by Mlem000)

The Version 4.8 summer event that takes us into another world, one created by 3 members of the Hexenzirkel (a "witches" coven based in Mondstadt that have a pulse on things) Alice, Barbeloth, and Andersdotter. Written by Andersdotter(M) determiner of their fate, brought to life by Alice(A), and who's inhabitance are guided by prophecies from Barbeloth(B). Along side the initial creation of this world Andersdotter created Durin. In doing so, as she was told by Barbeloth this Durin by virture of simply sharing a name will be bound to the real Durin's fate. He would live desiring companionship, be unable to obtain it, and die alone misunderstood. Even still she chose to bring this Durin into existence. She knows the history of the real Durin and found it sad, creating this Durin in hopes that he could have a happier ending, that maybe one day his fate maybe changed by a hero. A hero who's party would allow Durin's wish to be fulfilled. Until then she cared for him as her own child, reading him stories up till her passing. His mother left to become one of the stars in the sky, forever watching from above yet so far out of reach. And just like that Durin found himself alone, unable to approach anyone in the world all due to the nature of his own being. He stays like this, for a long time after his mother's passing yearning for her, the only person he was ever able to be close to; wishing to not have even been born in a world that'd never accept him (sounds familiar, how odd). It's that wish that invokes something, a change.

One day we find ourselves "invited" by Alice to a fantastical world of paper animals and clockwork people. A whimsical world that apparently has some trouble. Unbeknownst to us we aren't the only visitors; a king, a fairy, a hero, and a nekomata have all been summoned to this world, all individuals who held copies of Andersdotter's book brought into this world to fulfill their given roles.

We first spend our time in the forest where we find the inhabitance that speak about the coming of the hero; of course we think we're the hero and that we're here to save the world. Although when first told we apparently don't fit cleanly. We're also told of an attack by a dragon that's damaged a tavern inturn threatening the forest's inhabitance due to a lack of ink (the forest animals are made of paper and consume ink. Without this ink they not only loose their color, but their memories as well, and can die after enough time). We meet Nilou, the fairy of the forest and make quick work of the ink situation. Restoring color to the forest and restoring ink to the taps of the tavern.

Seemingly following the trail of this dragon we head towards Constellation Metropole meeting the nekomata Kirara (she was asleep in one of the train cars, +1 to party size). Once there we find that the dragon has stolen stars from the sky; causing some to fall while also interfering with the prophecies of the citizens. The people here are clockwork like, they have keys in their backs that slowly turn, winding them down. Once it stops turning that's it, they dead. With the interference to the goddesses magic due to the dragon "attack" the citizens find themselves stuck in cycles they can't escape from. Meeting the king, Navia; we of course deal with the situation but this is the point where we begin to learn about the dragon, Durin (of course, no surprise already said his name, no reason to act like it's a mystery. Although at the time going through the quest it was and after Metropole our attitude towards him shifts). We also find out why he's been stealing the stars, he's looking for his mother. As she said so long ago she'll be a star in the sky watching from above, he wants her back.

We chase Durin down to the end of the world where we meet the hero, Wanderer. He saves us from a fall afterwards lamenting his inability to leave this world (I love the fact that he's been here for days trying to escape, but just can't. He's literally trapped, proper isekai) while of course stating that he is not the hero (they all have items or at least some of them do, and Wanderer as the hero has a sword. Something he keeps throwing away just for it to reappear at his side). Doing the "I'm gonna skip stuff" our party perseus Durin into his domain, as we do so he retaliates doing everything in his power to stop us. Eventually he himself decides to fight back. It ends with everyone passing through a mist and effectively entering what is Durin's home, the place Andersdotter raised him. Also from passing through this mist everyone is treated to fractions of Durin's history, Wanderer the hero learns it all (seemingly better understanding why He is the hero and not anyone else). Something I skipped over is that each one of them heard a voice (From Alice of course) telling them what their purpose in this world is. Although he doesn't reveal it for a while, Wanderer states he the hero was sent here to save the dragon. As we approached him and fought him Wanderer has been . . . more cautious and weary (than what's normal for him) in engaging with Durin. Once he learns his name he actively corrects people helping to humanize Durin and his plight. Once the party learns the sad story of Durin the Simulanka dragon everyone looks at him differently, more importantly Wanderer who knows of Durin's wish warns him of asking for such a thing (Not wanting to have ever exist is something Wanderer can sympathize with, its something he's even attempted (read about it here, the whole helps to better understand but one could jump around)).

There's a bit of parallelism that's present with Wanderer & Durin (spoilers they become friends). They are two people who've been left behind by their mothers (putting it nicely, Durin's mother passed away, what can you do. Wanderer's mother just straight up abandoned him. These two things are not equivalent, but they both have similar effects on the two. They're alone left to stew in this reality) forced to wander looking for a place where they can belong. They both attempted with varying levels of success but at the end did not find places that truly desired them (The Fatui used Wanderer can't say it was his home, more here. Durin couldn't even communicate with others in the same book as him. They either found themselves afraid and ran away or fought back, and that's ignoring the I distort the world around me aspect of Durin) But Wanderer did, his place in Sumeru is that (He has a new mom now and No Ei can't have him back. Nahida loves and cares for him, and is even putting him though Academia. Under the Vahumana, history school for his old Ass. Maybe he'll become the sage for the school). And now as he stands seeing someone, possibly the only other person that has shared in his experience he wishes to help him (He won't say it but his actions say otherwise). He asks for Durin's real wish, what he tryly wants; to be accepted by this world and make friends. The Hero, the fairy, and the King make it so; giving him their blessing.

In doing so he transforms, No longer is he the massive blocky toy dragon that corrupts everything he touches but now a mini dragon, Mini-Durin. A dragon that's starting down the path his mother desired for him so long ago by making his first friend Wanderer, by going out and meeting those of Simulanka that he's unintentionally harmed, and afterwards leaving the storybook behind to explore the world beyond.

The story continues. Having spent a fair time in Teyvat traveling with Wanderer, an "opprtunity" arises. With the threat that is Durin's prophesied rebirth looming over Mondstadt; Albedo with mini-Durin's permission plans to resolve this by giving mini-Durin a human body. A human body with the abyssal heart of Durin (as we learn, this was something Rhinedottir was supposed to carry out herself but . . . she went off to be one with the concept of life I guess)

(Durin the Author; Recent Quest shit)

Why is Durin Nibelung (The creator of Teyvat, King of the dragons, Creator of the 3 moons)? Like Obviously he's not but why does his story parallels Nibelung's (Both Dragons birthed alongside their worlds (wonder if that means that Nibelung has a "mother" that's given him this world as his first and last gift? Guess that'd be another reason for him to fight back soo hard against the Primordial One / Heavenly Principles))? This also reveals a parallelism with Wanderer. If Durin is Nibelung, then Wanderer is Voyager? Again, not band for band, but loosly. Both Wanderer and Voyager enocuraged their respective dragon to leave or travel beyond their world. With Durin and Wanderer it was simlpy to voyage across Teyvat, with Nibelung and Voyager its to travel beyond Teyvat. Both dragons are changed or alteast mature from this.

Going back to the question of why the parallelism, the answer might directly be due to the Hexenzirkel. Although Simulanka is a story world written for Durin by his mother Andersdotter, it was still used to model concepts of Teyvat by the Hexenzirkel. The systems of fate and prophecy for example. Durin by virtue of his name alone is supposed, and destined to follow the fate of the first Durin, something we hear and are told about time and time again. In Durin's character quest "The Magic Known as Storytelling" we see Durin finally breakfree of this by appending his story onto the original Durin's story. Somthing that is a product of the Hexenzirkel (Not directly, but like they want to fulfil the wish of their long departed friend), something I'm sure they're interested in. It's a method of manipulating fate to their desire, it reveals a funtioning of fate in Teyvat. This is why Simulanka or more so what it allowed as a model. Mayde they didn't intend for Durin to map even partially with Nibelung, but that being the case my allow or reveal things that'd just never be known.