Back In Time As An Ancient Demon Lord.

(A/N:It should be noted that I will make some new skills unrelated but not far off from the tensura skill system. I'm also not the type of person to make Rimuru too overpowered for the battles ahead. I am making this fanfiction based on my imagination, so the events that play out might slightly differ from the original, so please forgive me for any wrong layout. )

 Leon's POV:

It's been years since the last tenma war, and it has been relatively peaceful... too peaceful for my liking. Ever since that bastard tried that prank, he has not made another move? which makes me extremely nervous. He has been inactive since then, and I am starting to feel a sense of déjà vu. Well,let's hope for the best and not the worst. I am now speaking to one of my guards. It was all going well when I received a call that would change my mood for the day.

Leon receives a call from Guy.

Guy: Hey Leon. Long time no see, right?

Leon: Guy, just what do you want this time.

Guy: Come on, why are you all behaving like sagging bags of depression?

Leon: I think you know why. Anyway, what did you call me for?

Guy: Right. I wanted to speak to you about Chloe and Rimuru. Something happened between them, and only I and Luminous noticed it.

Leon: What!! Guy, tell me what happened immediately! That wasted goo has never been up to any good ever since he started his pranking spree.

Guy: I heard from my maids that Chloe has been visiting Tempest more than usual. Ain't I right?

Leon: Yes, and what does that prove?

Guy: Aren't you curious about what they've been up to? I remember you and Luminous had an agreement that Chloe would visit both El'dorado and Ruberios due to her always staying at Tempest too much.

(A/N: Sorry if I spelt the name of any of them wrongly.🙏🙏)

Leon: Yes. So what does that have to do with your crucial information?

Guy: Haven't you seen that Chloe girl recently. She has been gaining weight.

Guy says this with a smirk whilst Leon grits his teeth in anger

Leon: Are you trying to say that Chloe is fat?!

Guy: Oi. Don't jump to conclusions on your own. What I am trying to say is that she has been behaving strangely, and her magicules have been unstable at her abdominal side, and that happened after her last tempest visit. What do you think.

Leon: If it is what I think it is, then I swear that slime is gonna pay for it! I've had enough of his stupid jokes!

Guy: (And here I thought he was a cool headed person. How love can make a great man fall.)

Leon: And what are you up to by giving out this information?

He says this with a face full of doubt

Guy: (Ha. I guess he's just as sharp as ever. I need to come up with an excuse.) Well, you know I've been bored lately, and I just found something of interest in your fight, so think of it as watching a showdown.

Leon: Fine. But make sure to stay out of it.( I don't know what he is up to, but I'll focus on Rimuru for now.)

Guy: Sure thing. Make sure to make it interesting.

Guy cuts the call.

Guy: As expected, Leon is no fun at all. I thought he will over react or something.

Rimuru: Well, he has always been a party proper and will always be a party pooper. Heck, he might evolve to a chaos grandpa if he goes on.

Guy: How will you deal with Leon and Luminous now.

Rimuru: Well, for Leon, I'll dump Carrera on him, and as for Luminous.... let's just say Veldora needs a vacation.

Rimuru says this with a wicked grin, which sends shivers to the Demon Lord's non-existent spine.

Guy: Speaking of evolution, it seems that doing paperwork for years has turned you into an evil scheme master.

[Back to the present time]

Rimuru: Remembering all those events does bring me joy. Remembered what happened after Carrera visited him? The dude nearly shit himself in anger. And Ruminas? I don't even think I can laugh without dying when she saw a sexy female Veldora. That illusion spell you created is the pinnacle of happiness.

Ciel: 'Master, that is a big waste of my skill.'

Rimuru: 'No, it is the most useful thing you've ever done.'

Ciel: '.....'

Rimuru: 'Oh, the silent treatment huh, whatever. But do you mind just helping me once, please-'

Ciel: No! Master, I was born to provide answers to various questions you ask and not to do your paperwork. The time you used for meaningless pranks could have been devoted to your work to make it shorter.

Rimuru: ( It seems Ciel hates paperwork as much as I do. I mean, we are the same with similar emotions and hobbies as she was born from a skill attached to my soul and also got affected by my soul, whilst developing her own emotions in the said skill. In other words, she has a part of my personality whilst carrying her own unique personality because of her being granted a soul by the VOTW during her manas evolution. Well, I can't blame her, I guess.)

Ciel: 'Master, I hope you haven't forgotten that I can hear your thoughts.'

Rimuru: 'Oi, quit listening to my thoughts. Scratch that, don't you know any way to have fun without escaping my duties?'

Ciel: 'There are many options, so you must mention things you want to do in order to find an appropriate action that is needed to take to fulfil your wish.'

Rimuru: 'Well, I kinda wanna fix this problem of mine in order for me to get a little free time. I also wanna spend some time with my friends. It's been a long time since we had anything fun to do together. I also wish that I could outright deny any requests or demands from those pesky demon lords, especially Guy. Always using the excuse of me being a newbie demon lord to push responsibilities and tasks to me and once that happens, everyone goes with the flow and at the end of the day, I always get the short hand of the stick. I also wish I could have saved some of the people I couldn't save like the ogres of Benimaru's tribe, Ranga's dad and some of my subordinate's loved ones.'

Ciel: 'Why would you want to do that?'

Rimuru: 'I noticed that they've been happy staying here in tempest yeah but I'm sure deep inside, they still want to spend time and catch up with them like how I do.'

Ciel: 'If that is the case I don't know if you would accept this but I might have a solution to your problem.'

Rimuru: 'Why did you sound reluctant to tell me but speak up? I'm all ears.'

Ciel: 'How about going back in time to-'

Rimuru: 'Alright I know you can do some crazy shit at times but WHAT!!'

Ciel: 'It is advisable to listen to my explanation before cutting in to avoid mistakes.'

Rimuru: (Is she mad at me?)

'Y-Yeah, sorry about that.'

Ciel: '*sigh* All the wishes you made could be solved by going back in time and about the Demon Lord problem, by becoming an Ancient Demon Lord alongside your strength, you would be respected and being forced to do unwanted tasks will be a thing of the past. You would also be able to spend time with your friends and rebuild tempest with your knowledge of how things work and also fix your mistakes. It will be a new journey with the inclusion of the events that transpired before your birth.'

Rimuru: 'After your explanation I am actually excited about it but if I do that, tempest will have no one to oversee it and I can't do that.'

Rimuru finishes the last batch of his work and when he tried to think of going to the labyrinth, he got interrupted by a knock on the door. It was Shuna and she wasn't carrying a tray for tea or a tray of snacks, she was carrying a long stack of papers that needed attention. When Rimuru saw this, he tried to jump out of the window but was held by the hand and when he turned around to look, he saw Shuna with a smile that screamed instant death. He could do nothing but sit his ass down to continue his renewed torture session.

Rimuru: 'Ciel... I swear if another stack of paper passes through that door I'm gonna commit genocide.'

Ciel: 'Master, I created a new skill called {Multiple Parallel Existence} that solves your problem of staying in tempest whilst travelling back in time.'

Rimuru: '...'

Ciel: '...'

Rimuru: 'Ciel-san~. You mind telling me when you had the time to do that.'

Ciel: 'M-Master i-it was t-the skill I was creating d-during the

time you complain o-of-'

Rimuru: 'YOU HAD THE SOLUTION ALL THIS TIME AND YOU FUCKING KEPT IT TO YOURSELF?!!'

Ciel: 'Sorry Master, I just finished ensuring the safety of the skill and I will make it up to in this journey.'

Rimuru: '*sigh* I thought i couldn't use {Parallel Existence}

because I hadn't mastered how to split my consciousness into other bodies.'

Ciel: 'Which is why I created this skill. It does not require the process of splitting the user's consciousness but rather, making an entirely new consciousness on its own without any casualty. The said skill does not only have all the skills the user possesses, but also has the same amount of magicules as the user without any cost of magicule loss at the destruction of the said body whilst being able to create more consciousness compared to {Parallel Existence}.'

Rimuru: 'Hehehe. You've really out done yourself Ciel. If Velgrynd learns of this achievement, I'm sure she'll get some serious depression. How lucky I am to have you.'

Ciel: 'Hmph! You know you can praise me more maste-'

Rimuru: 'I'm still mad at you.'

Ciel: '.....'

Rimuru: '...Come on~. You know I'm just kidding hahahahaha.'

Ciel: '....'

Rimuru: '....Can you just....give me an update of myself?'

Ciel: '.....Yes master.'

Name: Rimuru Tempest

Existence Value: 271,681,123

[+Tempest Blade 19,189,220]

[+TD Release 242,476,666]

Race: Supreme Chaos Spirit:Viscous Draco-Demonic Void God Body. [Ultimate Slime],[Digital Lifeform],[Imaginary Lifeform]

Blessings: Grace of Friendship

Title: Ruler of Monsters, True Demon Lord, King of Jura Tempest Alliance ,Chaos Creator, Void Dragon

Manas: Divine Manas:Ciel

Intrinsic Skills: Universal Perception, True Dragon's Haki, Universal Shapeshift, Information Particle Manipulation, Ultimate Existence,

Ultimate Skills:Void God:Azathoth Harvest Lord:Shub-Niggurath, Lord of Lost Souls:Asura, Lord of Causality:Sidon

Magic: True Dragon Magic, Summoning Magic, Holy Magic, Dark Magic, Elemental Magic, Spirit Magic, Physics Magic

Resistances: Physical Attack Nullification, Pain Nullification, Spiritual Attack Nullification, Natural Effect Nullification, Abnormal Condition Nullification, Holy-Demonic Attack Nullification

Rimuru: 'Oi Ciel! When did I acquire two new ultimate skills and what's up with the imaginary life form thingy? Plus, I don't remember having new intrinsic skills.'

Ciel: 'Master, the alterations were necessary for this new adventure and were developed for safety reasons.'

Rimuru: 'Safety reasons my ass! You just wanted to play with my skills, didn't you?!'

Ciel: '...'

Rimuru: 'Your silence is all I need. *sigh*. Seriously, just tell me next time you wanna do that. Well, I'm gonna need to know what these new skills do.'

Ciel: 'Hai!'

[Soul God:Asura.]

[Subskills]

1. {Soul Harvest}: A subskill of Asura that can reap the soul of any individual who does not have nullifications against soul assaults. Even if the said individual is in possession of an ultimate skill, as long as the condition is fulfilled, the soul will be forcibly taken away from the material body alongside any skill (including ultimate skills) or material within the soul. This is a multipurpose skill that can be used in many ways.

2. {Soul Resonance}: A skill that allows the user to temporarily achieve a state of absolute soul purity. This skill cleans the user's soul of any negative energy and also purifies any kind of magical, spiritual and mental effect approaching or affecting the user with the exception of pure physical attack by encasing the user with an effect negating soul energy. This skill also works on all ultimate skills that have not reached the God-level. But if the user's willpower is strong enough, even God-level Ultimate Skills will not be able to affect the user.

3. {Soul Absorption}: Allows the user to constantly absorb or deplet an individual's soul energy until it has been completely erased. It can only be countered by having a soul attack nullification type skill or an ultimate skill at the Lord-level.

4. {Soul Restoration}:Allows the user to make a perfect copy of their soul that can serve as replacement if their initial soul gets completely erased. If a copy

of the soul is not prepared before the destruction of the original soul. The user will die nonetheless. It also takes 9 days for a new soul to be copied. The copied soul retains the memories and personality of the original soul with no memory loss whatsoever. It also allows for the replacement of souls for other individuals as long as necessary information about the soul is available.

5. {Soul Domination}: The user has perfect control over any soul related activity. With this skill, the user can manipulate any attack to directly affect the soul whilst having strong resistance to soul destroying attacks. Also, soul magic and resurrection magic have high chances of success.

6. {Infinite Soul Regeneration}:

The skill {Infinite Regeneration} increases the speed at which the soul regenerates from damage. Normally, {Infinite Regeneration} takes about half a day to heal from thirty per cent Soul damage, but this skill allows for regeneration of the soul from fifty per cent damage to completely heal for a few minutes.

[Lord of Causation: Sidon]

[Subskill]

1. Analytical Appraisal

2. All of Creation

3. Law Domination

4. Causative factor

5. Causality Collapse

Rimuru: '.....You know what, I'm officially sealing that Asura skill until it is needed. And can you explain the subskills "Causative factor" and "Causality Collapse"?'

Ciel: 'Yes. Basically, causative factor is a skill that unveils the cause or reason for any occurring events. It can provide the user with detailed information concerning the cause of an event.

'

Rimuru: 'Really? That's so cool. So, within a fight, I can find a reason for my opponents strength or action! I can also find a reason why I don't have a son!!'

Ciel: '...'

Rimuru: 'Ehem. Please continue with the other subskill and the new intrinsic skills.'

Ciel: 'The second subskill 'Causality Collapse' is a very powerful skill that can eliminate the cause or reason for anything that happens. This skill erases the primary cause of an event as long as information of the primary reason is known. It has no limits and is capable of even easily wiping out individuals who do not possess Lord-class ultimate skills .'

Rimuru: 'What in the actual f*ck is this skill!! It's too broken! I have a subskill that can find a reason behind anything, and then there is this skill that will erase that cause! I am also sealing this skill. If Guy or Elmesia found out about this skill, they're gonna start a teaching lesson about common sense.

Ciel: 'Yes Master. Also, the intrinsic skill {Ultimate Existence} is a skill that allows the user to temporarily possess more ultimate skills without any damage to the soul. It also allows the user to infuse the essence of their ultimate skills with themselves, allowing them to become one with its law and power. And about the imaginary lifeform, it is a new type of lifeform that manipulates turn null energy without collateral damage. It also allows the user to convert themselves into turn null energy itself and back into their original state with no loss'

Rimuru: 'Well, it's an intrinsic skill, so there is nothing I can do about it, but what about travelling to the past thing. Do you have a solution for that?'

Ciel: 'Yes. With the skill {Time Warp}, master can transcend time and space to reach your desired location.'

Rimuru: 'Wow. You really planned ahead for me, didn't you? Thanks a bunch, Ciel.'

Ciel: 'Hmph! Everything I do is for you master.'

Rimuru: 'Yeah, yeah, I know. Quit flirting with me and start the plan already.'

Ciel: 'Yes.'

After that discussion, a black smoke exits Rimuru's body, creating another copy of himself. As soon as the process was completed, the parallel existence tried to jump out of the window but was caught by Rimuru, who grabbed his hand tightly whilst displaying an angry expression.

Rimuru 1: Oi. Where do you think you're going to?!

Rimuru 2:Don't fuck with me you idiot!! Did you really think I would sit here and do your stupid work when you get to fool around the world?! You're the most hopeless bastard I have ever laid my eyes upon. I'm gonna steal your plan after escaping this prison. Hahahahahahahaha! Hahahahahaha! I'm a genius ain't I right Ciel?!

Rimuru 1: Then why don't we make a deal. I go do my plan whilst you help me out then when I get back, you have your turn eh?

Rimuru 2:I see. But I'll only agree if I get to spend a longer time out than you.

Rimuru 1: Yeah yeah. Fine. Rhwn you stay her me whilst I'm gone.

As soon as Rimuru said this, he got surrounded by glowing light implying that the time warp skill had been activated. He waved goodbye to his other self then he disappeared. Not without revealing an evil smirk.

Rimuru 2: Hehehe. I'm gonna spend more time out than him. The fool did not even that realise I could also experience all that he's been through. Ahh. What a genius I am.

Meanwhile Rimuru has already successfully made it back to the past.He checks his surroundings to see if he made it before smiling at the result.

Rimuru: It seems that we made it huh.

Ciel: 'Yes master. This is the time period before milim became a demon lord.'

Rimuru: 'I see. Heh, that idiot didn't even know that I can deactivate my skill if I want to.

Seriously. What a fooļ he is

Ciel: 'Master, you do know that is you.'

Rimuru: '...'

Ciel: '...'

Rimuru: 'To become a demon lord it is!'

Ciel: '*sigh* Yes master '

Rimuru: 'And Ciel, do you mind limiting my power a bit? Don't wanna ruin the whole fun in a fight right?'

Ciel: 'Yes. But to which level do you want your power to limited to?"

Rimuru: 'Well just make me as strong as when I fought Milim in her stampede mode during the great tenma war. And also, I only need Azathoth, so you handle Shub-Niggurath. I don't see a need for having those new ultimate skills but since you are the one that made them, I guess they might have its time to shine so just let them be stored in my {Skill Storage}.

Ciel: 'I understand. Master's EV has now been limited to 108,681,123.'

Rimuru: 'Yosh! That will do just fine. I can't wait to start this new adventure.'

And with that, they set out to start their new journey together.

(A/N:Yeah. The new ultimate skills are not the only ones I plan to add. What do you think of them. Aren't they op! A lot of people use Hades for ultimate skills involving souls so I made mine different although Asura has nothing to do with souls. But I am the Author so you have no choice but to read it. Sucks to be you right? Hahahahahahahaha. Ahem. Forgive me for that. Anyway, I plan to make this a long fanfiction based on how Rimuru interferes with past events. As I said earlier I don't like making him too op but later realised that the difference between demon lord Rimuru and true dragon Rimuru is vast so I just used the true dragon Rimuru that fought against stampede Milim. I also felt that in the LN Volume 19, when Rimuru defeated Michael, he absorbed his soul, alongside his large pool of magicules which was said to be greater than an EV of 100 million

so it will only make sense that his EV will also be above 100 million since all the times he used Beelzebuth to devour his targets, his own magicule pool increases. Thanks for reading my works and I hope you look forward to my future works. See yah!)