Five Hundred years had passed since (Y/N) had first arrived in Teyvat. During that time, he managed to get attuned to his new abilities and accept that this was his new life. Though many years had passed since his reincarnation, it was a mere fleeting moment since he no longer physically aged.

Currently, (Y/N) was at the top of Mt. Aocang, where Cloud Retainer often resided. Alongside him was Ganyu, whom he had grown relatively close to in the time that they knew each other.

Overlooking the landscape, he held the strings of his bow that he had copied from Ganyu back as cryo began to infuse within his arrows.

Amos Bow

Ganyu: You can do this, (Y/N)!

(Y/N) closed his eyes as he inhaled and focused on the two elemental monuments that floated on the small rock formations in front of him. Opening his eyes, he exhaled as Ritsu targeted the trajectory of his arrows.

Ritsu: [Target acquired, calculating arrow trajectory]

In quick succession, (Y/N) fired off two arrows infused with cryo, which hit their marks. As soon as the elemental monuments lit up, a large updraft appeared as (Y/N) took off at inhuman speeds. As he neared the edge of the mountain, two large bat-like wings sprouted from his back, and he jumped into the updraft.

Using his momentum and the updraft, (Y/N) flew upwards into the sky. (Y/N) flew into the Anemo rings, which redirected him to the next target. Upon landing, he fired off another arrow to light the monument. Like before, he flew off and continued through the training course.

After completing Cloud Retainer's training course, (Y/N) flew back to Mt. Aocung, where Ganyu and Cloud Retainer was waiting for him.

Cloud Retainer: Well done. One can see that your training is paying off.

Ganyu: She's right. You completed the course faster than last time.

(Y/N): Thanks, you guys, but I couldn't have gotten this far without either of you.

Cloud Retainer: Rest up. We shall continue your training tomorrow.

The Next Morning

(Y/N) was lying down in the grass under the shade of a tree when a shadow blocked his view. Opening one eye, (Y/N) saw Ganyu standing before him.

(Y/N): Hmm? Oh hey, Ganyu, what's up?

Ganyu: Morning (Y/N). Time to get going.

(Y/N): Five more minutes.

Ganyu: But we have a lot to do today. We shouldn't just laze around.

(Y/N): You need to relax, Ganyu. Come, lie down on the grass with me.

Ganyu: Well... okay. But only for a few minutes.

Ganyu lay down on the grass next to (Y/N) as the two used this time to unwind for a few minutes.

Ganyu: I have to admit... It is rather lovely to relax for a few minutes.

(Y/N): See, what did I tell you?

(Y/N) winks at Ganyu, causing her to blush.

Ganyu: A-anyway, It's like I can feel the heartbeat of the world.

(Y/N): It's incredible, isn't it? Most people take the world around them for granted, but when you stop to take a moment to let everything around you sink in, you start to see the beauty of the world.

Ganyu: I guess I never thought of it that way...

(Y/N): Come on, we should get going now

Ganyu: Right.

Both (Y/N) and Ganyu get up and start making their way over to Cloud Retainer's location. As they walk, (Y/N) gets a feeling of unease.

(Y/N): Why do I feel so uneasy all of a sudden?

Ritsu: [Notice: Cannot Calculate]

Ganyu notices (Y/N) stop in his tracks as a look of worry sets in on his face.

Ganyu: (Y/N), is everything alright?

(Y/N): Something feels... wrong...

Ganyu: Maybe it's just your imagination?

(Y/N): I'm not sure, but whatever it is, it's-

Before (Y/N) could finish, a loud voice rang out in the distance in a melodic tone.

???: AAAAHHHHHHHH!!!

Ganyu and (Y/N) looked at each other in concern.

Ganyu: Y-you heard that, right?

(Y/N): Yes, though I'm not sure what it was.

Ganyu: It came from that direction!

Ganyu pointed in the direction of the loud voice. (Y/N) and Ganyu's eyes widened upon realizing that the sound was coming from the Guili Assembly. The two sprinted to Cloud Retainer, who looked worried about the situation.

Cloud Retainer: Is one to assume that you both heard that sound?

Ganyu: Yes, it came from the Guili Assembly. We have to go now!

Cloud Retainer: Very well. (Y/N), if you would.

(Y/N) nodded as he opened up a portal that took the shape of three blue stars. The three Adepti walked through the portal, which led them back to the Guili Assembly: Upon exiting, they noticed that the city was under attack by a large creature with an aura of malice.

Tiamat

The Guili Assembly was in utter chaos as the giant creature, Tiamat, was rampaging through the city. Many locals panicked as debris flew everywhere and fires raged across numerous buildings. Morax and the Yakshas were on the front lines trying to fight Tiamat, to no avail. The other adepti used the ballistae Guizhong had created against the giant dragon. Meanwhile, Guizhong was helping to evacuate the civilians out of the city.

(Y/N): Come on, we got to help them!

Ganyu: Right!

Cloud Retainer flew off to aid the other adepti with the ballistae while (Y/N) and Ganyu made their way to the front lines to join Morax and the Yakshas.

Xiao: You two sure took your time!

(Y/N): Sorry we're late.

Indarias: Better late than never, cutie~

Bosacius: Less flirting, more fighting!

Indarias: Right, sorry.

Ganyu: What is this thing?

Menogias: We don't know. Everything was fine until this monster started rampaging in the city.

Morax: Whatever it is, we have to stop it.

Morax and the Yaksha charged at Tiamat, using their elements to attack the beast. In the meantime (Y/N) summoned his Polearm while Ganyu summoned her bow.

Morax summoned a giant meteor from the sky, which came crashing down upon Tiamat.

Morax: THIS IS ORDER!

Tiamat became petrified in a shell of stone, which it quickly broke free from.

Calamity Queller

(Y/N) infused Cryo into his Polearm and charged at the giant beast. He thrust his Polearm forward to attack the beast, but it had no effect as the Tiamat didn't even seem to notice. (Y/N) and the Yaksha regrouped to discuss a new strategy.

Bonanus: None of our elemental attacks are doing anything!

Indarias: What do we do now?!

(Y/N) it took a moment to think things through. Knowing the beast must have a weak spot somewhere, he thought of ways to be able to locate and exploit it.

(Y/N): I have an idea... but first, I need to test something quickly.

Menogias: Alright, we'll trust you. Just be quick

Ganyu: Be careful, (Y/N).

(Y/N): I will.

(Y/N) walked towards Tiamat, who was still rampaging.

(Y/N): Ritsu, look for any weak points

Ritsu: [Scanning for Vulnerabllities]

(Y/N): I hope this works...

(Y/N) imbued his Polearm with mass amounts of cursed energy. Using electro, he took off at an incredibly high speed and slashed at Tiamat with as much force as he could muster. (Y/N) landed to the ground, holding his Polearm behind him as he looked on. A large cut appeared on Tiamat as it roared out in pain.

Tiamat: AAAAAAHHHHHH!!!!!

Tiamat looked at (Y/N) with absolute rage as it saw the source of pain.

(Y/N): Looks like it worked, but I pissed it off in the process...

Tiamat furiously swung its claws at (Y/N) to try to crush him.

Ganyu: (Y/N) look out!

(Y/N) tried to move, but the beast's fury had drawn all attention to him as it kept trying to crush him. As Tiamat's claws came down on him, Ganyu and the others looked on in horror. However, to their surprise, Tiamat stumbled back. As the dust settled, (Y/N) stood there unharmed.

(Y/N): Damn, Infinity is really overpowered.

Tiamat: AAAAHHHH!!!!

Tiamat attempted to swipe at (Y/N), but he dodged the attack by sprouting his wings and flying into the air.

(Y/N): Ritsu, find anything yet?

Ritsu: [Notice: This being is being influenced by a foreign source of corruption]

(Y/N): So something is compelling this beast to destroy things against its own will?

Ritsu: [Answer: Correct, locating corruption source]

(Y/N): Then we have to find a way to free it.

Ritsu: [Notice: Caution should be taken when destroying the source of corruption]

(Y/N): Got it.

(Y/N) flew back down to where Morax, Ganyu, and the Yaksha were.

Ganyu: (Y/N), please tell us you found something.

(Y/N): I do, but you guys have to get out of here!

Indarias: You must be crazy if you think we're leaving you behind!

Morax: He's right (Y/N). We're not leaving you to deal with this alone.

(Y/N): I appreciate it, Morax, but it's too dangerous right now! Your people are going to need you after this! Don't worry about me.

Morax understood the point (Y/N) was trying to make and decided to put his trust in him.

Morax: I suppose you're right... just be careful (Y/N).

(Y/N): Don't worry. I will!

Morax, Bosacius, and Menogias went off to aid Guizhong. However, Ganyu, Xiao, Indarias, and Bonanus stayed behind.

(Y/N): What are you guys doing?! You need to get out of here!

Xiao: We're not leaving you.

Bonanus: N-no matter what you say!

Indarias: We'll be by your side!

Ganyu: Until the end!

(Y/N) looked back at them with a smile.

(Y/N): You guys... Thank you.

Xiao noticed Tiamat was approaching them, fixated on (Y/N).

Xiao: What's your plan?

(Y/N): Right, something is forcing this monster to rampage against its will. I'm not sure where it is, but I need you guys to buy me time until I can locate it.

Bonanus: B-but our attacks did nothing against it!

(Y/N): When I attacked it earlier, I created a large cut on its stomach. If you attack that spot, you might be able to distract it long enough to do what I need to do.

Indarias: All right, but you owe me a date after this, cutie~

(Y/N): We'll talk later. Right now, we need to focus on our objective.

(Y/N) flew off as Tiamat chased after him. Ganyu, Xiao, Bonanus, and Indarias caught up to Tiamat and focused their attacks on the cut (Y/N) they had made earlier.

Tiamat: AAAAAHHHHH

Tiamat's focus shifted to the attention of the four Adepti, attacking at the large slash across its chest. Meanwhile, (Y/N) flew around above Tiamat, looking for the corruption source. That was when he noticed a small purple spike on the back of Tiamat's head.

Tainted Blood

Ritsu: [Notice: Corruption Source located]

(Y/N): Gotcha

(Y/N) imbued his Polearm with cursed energy again and plummeted downward, using his momentum to plunge his cursed weapon into the purple spike. Tiamat had cornered the other Adepti, but as it was about to strike them, (Y/N)'s weapon made contact with the corruption source. Tiamat faltered as the source of corruption had been destroyed but had quickly grabbed (Y/N) with its claws. The dragon stared down (Y/N). (Y/N) started to turn into his slime form as he began to slip through Tiamat's grasp.

(Y/N): You have caused great anguish to those whose lives you have destroyed today...

(Y/N) began to wrap around Tiamat, which confused the giant beast.

(Y/N): You have committed many sins today, and for that... you will never see the outside world again...

As it roared in pain, steam began rising off Tiamat's body.

Tiamat: AAAAAAAAAHHH!!!

(Y/N): DEVOUR!!!

(Y/N) encapsulated around Tiamat as the slime consumed her.

Ritsu: [Skill: Immense Mana acquired]

Ritsu: [Notice: Due to the immense amount of power acquired, your body will enter a self-induced meditative state]

(Y/N) started falling out of the air.

Ritsu: [Skill: Authority of the Beast acquired]

Xiao ran over, leaping into the air, and caught (Y/N)

Ritsu: [Skill: Sea of Life acquired]

Xiao landed and ran over to the others. He passed (Y/N) over to Ganyu, who was holding him tightly.

Ritsu: [Notice: Demon Lord Seed acquired]

Bonanus: I-is it over?

Before anyone could respond, the wall on the nearby dam began to crack as water started to spew.

Indarias: You just had to jinx it, didn't you?

Xiao: Move!

The group made their way out of the Guili Assembly's ruins, which were starting to flood due to Tiamat's rampage. After making their way to safety, Indarias and Bonanus looked at (Y/N) with concern.

Bonanus: W-will he be alright?

Ganyu: I hope so... he just needs some rest.

*MEANWHILE*

(Y/N) awoke in his soul scape. As he looked around, he saw Ritsu waiting for him.

(Y/N): Ugh...Ritsu? What happened?

Ritsu: [Answer: After Ingesting Tiamat, your body was forced into a meditative state]

(Y/N): Tiamat? So that's its name?

Ritsu: [Answer: Correct, Tiamat has successfully been ingested and restrained within your soul-scape.

(Y/N): I see. Can you take me to it?

Ritsu nodded and started to walk off, with (Y/N) following closely behind. Suspended in the air was a woman with long silver hair and two large horns whose limbs were held back by yellow cubes to prevent her from moving.

Tiamat (Human Form)

Tiamat: Aaahhhh? (What is this?)

As Tiamat spoke, something had changed. (Y/N) was able to understand her now. Tiamat looked up to see (Y/N) and recognized him.

Tiamat: You... you're the one who stopped me, right?

(Y/N): Indeed, so you're Tiamat?

Tiamat: W-wait, you can understand me now?

Ritsu: [Answer: Due to (Y/N) consuming you, a psychic connection has been established, which allows the both of you to understand each other]

Tiamat: He... consumed me?..

(Y/N): You were on a rampage, and it was the only thing I could think of to stop you.

Tiamat: I see... so this space... is inside of you?

(Y/N): Well, more like inside of my soul, to be exact.

Tiamat: It's so peaceful here... the pain... I don't feel it anymore.

(Y/N): You're in pain? What happened to you?

Tiamat: I'm not sure... somehow I ended up in this world in a state of slumber... but when I was asleep, I felt tremendous pain... like something was happening to me in my sleep... It was dark and cold.

(Y/N): So you're not from this world?

Tiamat: I think so... I can't remember much of where I came from before I arrived here... but the world is unfamiliar. Why do you ask?

(Y/N): Because I'm not from this world either.

Tiamat: I see... so in that way, we are kindred spirits...

(Y/N): I guess we are. Do you remember what drove you to go berserk?

Tiamat: Right... I think I was deep underground... I saw many humans... they were doing something to my cocoon... I'm not sure what..., but it hurt... it hurt a lot... Then I heard a voice call out to me... it said I would reawaken and destroy everything in my path. It corrupted me with something powerful from the abyss... I tried to fight against it, but I couldn't control myself... something kept pushing me... the voice... wanted me to destroy you...

(Y/N) eyes widened after hearing about a mysterious voice commanding Tiamat to target him. He shuddered at the thought that Asmoday was behind this.

(Y/N): Did this voice say anything else?

Tiamat: Just his name... he said he was called the Dragon of Demise. He used his powers to corrupt me... to taint me...

(Y/N): I see. Thank you for the information.

(Y/N) started to leave, but Tiamat called out to him.

Tiamat: W-wait! What about me?

(Y/N) stopped and turned to look at Tiamat

(Y/N): What about you?

Tiamat: You're just going to leave me here chained up like this?...

(Y/N): Tiamat, whether in control or not, you still committed numerous atrocities. You will be confined here for the rest of time to atone. Besides, I can't let you out in case this Dragon of Demise tries to corrupt you again.

Tiamat looked at (Y/N) with downcast but understanding eyes.

Tiamat: I see...

(Y/N): Don't worry. I'll come and visit you if you want.

Tiamat's head perked up, and she looked at (Y/N) in shock.

Tiamat: Y-you mean you would come to visit me even after everything I've done?!

(Y/N): Well, of course. Just because you almost murdered all my friends and destroyed my home doesn't mean you deserve to be alone. Besides, it's not like you can do any harm in here.

Tiamat: You're a little crazy, you know?

(Y/N): Honey, I'm a cursed 17-year-old kid who was reincarnated as a slime and has lived for hundreds of years. I think I'm beyond "a little crazy" at this point.

(Y/N) started to walk away as he snapped. The yellow cubes that held her in place dissipated, freeing her from her suspension. As soon as she got to the ground, she got up,