SKILL COMES ONLY THROUGH TRAINING!

After Orcus told me his name, for some reason, it feels like my body was sliced into pieces, with only my head remaining. But it turns out all of that happened as I look up at the figure approaching me; it becomes clear I get to see what a demon spirit actually looks like. Why am I still alive? How is it possible, I wonder?

                                  "Ha ha ha ha!___ After all that you still have the will to think." So Rukito was it? Interesting ; this will be fun ."    

"How do you know my name? " (Rukito struggles to speak as he is in unimaginable pain.)

                        "Ooh, I just looked into your memories. Quite a pathetic person you are, I see." You think you can rule the world by helping humans with magic, and look what happened to you? Now you're here thinking you can gain the skills of a Sword Master, but skill comes only through training. "I spent millennia just to obtain 5% of my power, and 1% can wipe out the whole universe with a swing of my hand. I am the strongest person you could ever lay your eyes on. I bet even if I trained you for a thousand years, could you even lay a finger on me?"

"I bet you're such a bad teacher. You'll blame your lack of teaching abilities on being so simple-minded and never mastering any of them. To truly call oneself a master is to have the ability to teach what you know, for you can only truly understand your abilities if you have the capability to explain them and teach others."

                          "Oh, I see what you're doing, but I'll bite. I'll teach you until you have the capability to cut off my arm. We can start with healing. I was going to heal you, but you think you're so smart. So for lesson one, I want you to master healing; your body will be fully healed by yourself. I hope you enjoy pain because it’s not going to be easy for you."  

fuuuuuck!!

Lesson 1 
Healing is a talent few people are born with. The healing magic that is used requires you to use mana to speed the process of healing a wound. But there are many flaws in that, so my way is much better. Learn the anatomy of your body first. Only when you know each and every part will you be able to heal yourself perfectly.

Lesson 2 
 It's different for you because you don't use mana, and I never studied elves, so try using the energy from the World Tree to heal. The World Tree never runs out, so you're quite lucky to have access to it.

Lesson 3 
Use lessons 1 and 2 to recreate and reconnect damaged parts using the energy from the World Tree to recover and heal. Good luck.

What happened to magic being easy? Why do I need to study things like anatomy? That, too, is not basic; it's every single aspect of it. Not to mention, half the stuff here makes no sense.

After explaining, Orcus gave Rukito some books as he enjoyed looking at the amount of pain he had on his face. After 10 years, Rukito finally healed his chest, right arm, and hand. With that, he can now turn pages himself. Almost 70 years later, Rukito fully healed himself, shocking Orcus, as it took him 150 years to fully master this. After that, Rukito mastered regeneration, which requires every cell in his body to remember how to put itself back together. Sounding much harder than simply healing, Rukito took only 30 years to master it, thanks to the support of the World Tree and its natural healing capabilities. 

                "Hey , before I teach you combat I want you to fight me with all you have so I can see how good you are and where we should start."

"Sure, there aren't many people who can beat me, so here we go."

The moment I said "start," he disappeared before my eyes and reappeared as I fell to the ground, helpless. Before long, I fully healed in under 2 seconds. The moment I healed, he attacked again; countless times this repeated, and I lost count. It's like he's having fun cutting a tatami mat that never runs out. As time went on, I started to forget the pain and think of ways to counter.

(1 year later) He comes at me as always before his speed rapidly increases, but this time I speed up my perception while vibrating every cell in my body to avoid his attack. Before he attacked again, he stopped. That was a success on my part but avoiding 1 attack won't save me from facing death.

                  "Where'd that come from? For a year straight, you were as good as a tree, helpless with no way to avoid death, but now you've moved. Now you're a cat that avoided a falling bookshelf, only to jump out the window to be taken down by a violent river stream."

"One year straight! You beat the hell out of me, and I had nothing. With my teleportation and perception, I was at best as fast as sound, yet you came at me with full speed, taking me a year to adapt, and you had the nerve to ask where I got it from. It's from the countless times dying; well, I can't die from any sword, but still. How is this teaching? This is torture."

                    "You now move faster than light; be happy that you could push yourself that far. After countless years with you, I can say that you can reach my level in a thousand years, which you should be proud of."

"That's fine... I guess, but now you need to teach me properly because if you continue like this.... Never mind, anyways, maybe teach me a way to use powers without the use of mana."

                       "I was getting to that, so I'll get started. There are many sources of power that even you yourself use unknowingly, but what I'm going to teach you is advanced. I'll start by explaining the type of source energy I'll teach you to use." :__

~ Chaos void 

It's known as a place that transcends dimensionality. A place outside and in between multiverses is also considered the Chaos Void. The Chaos Void exists in this world as well as the next, unable to be perceived. 

For your information normally it would be impossible to learn to use this type of source energy but you have the aptitude so its fine. 
Now the first step to this is:

Void Perception   
 You can't access something you can't perceive, so your first step is to feel the Void Energy (VE) around you. 

That's the first part of this training. With this, you'll know where to pull energy from and how to use it. I don't know if you've realized it, but your teleportation uses VE, so using it won't be hard. You can now use this for more than just teleporting. The skills I'll teach you using the power of VE are not the elemental magic you know of, but VE is capable of that. However, why use that when you have Void Rift, the ability that ignores all defense, cutting through the world itself to slice the target in half? Another useful ability is White Vacuum, which removes everything in a small space, leaving nothing and causing everything around it to implode. It's a single-target skill that won't cause unnecessary damage, unlike Black Hole—the more destructive way that wipes out not just the opponent but can destroy the whole galaxy. This move will not stop even after the caster dies, so you yourself need to nullify it, which is harder than learning the skill itself but worth the effort you put in.

Now for more supportive ability's

Time Manipulation
The ability to control and manipulate time is not something that’s easy to learn, but first, I need to teach you how to resist a time stop, as it's the first step to learning time manipulation. You need to become a fourth-dimensional being for that; luckily, you are halfway there.   

Note that you can build apron what I teach you its not be all end all. But I don't think you can surpass my way of thinking 

Stage 2 is a little different, as I want you to improve your physical strength. It’s not easy for a weak person to control destructive and chaotic concepts. With this, we can also work on your speed, as well as your control over it. Maybe I'll also prepare you for your sword training, so every day in the morning, do 1 million sword swings, and each day, I'll increase the weight of the sword by 2.   

Stage 3 mastery of Void Energy =( VE )
Mastering a power like this opens the door to my favorite part of this, which is the undead. There are two types of undead that split into different categories.
Basic and True perfect 

Basic: zombies ,ghouls ,skeletons ,mummies ,wraiths and liches

zombies being the easiest to make with the least destructive power and liches being the best in this category capable of thinking and can cast magic but all inferior 

True perfect:
Undead at the highest level are all immortal. All basic undead can achieve true perfection and also become immortal, but there are undead races that start in the true perfect category. 
They are : vampire's and Whole Zombies 

( Whole Zombies can only be made if the copse is completely intact and they are turn within a day and has the original soul of the corpse . This may be considered reresection but its not )

Stage 4 -Metaphysical Void Energy 
This is where you are able to create things out of nothing. Any type of object can be created using this power. This is also a power that can come from strong emotions, wandering souls, and negative energy from the world. Yes, all the energy that people, animals, and the world itself uses can be harnessed by you with this. This power can serve any source of energy, so you'll be able to cast the magic you could use before but without limitations. Once you master all this, you will truly be able to use the Chaos Void as your source of energy, allowing you to become a being that can create and destroy reality itself and use infinite energy.

"Well all this sounds fun but with this power would I not be able 1-shot you?"

                 "You can try for a thousand years, but remember, I'm the teacher. How can you be better than me in what I teach you?"

Starting with the first part, Void Perception took the most out of my time, as I lost my emotions to time with nothing but training. If it weren't for Sayo's revenge, I would have lost who I was. After training for 800 years and learning about void perception and the skills and abilities that come with it, I became someone who forgot the joys of life, slowly making me like Orcus himself. However, the hatred I have still runs deep, and the motivation to build a harem drives me forward. The only rest I had came every 500 years.

After learning the first stage, the other stages never felt as hard when he explained them, but knowing that Orcus never speaks clearly made it harder to understand. If I hadn't been familiar with these concepts thanks to power scaling in overpowered anime characters, it would have been much more challenging. The physical training was the most brutal; the number of times I had to heal myself was more than counting every grain of rice in a 10 kg bag, but each time I healed, my body became stronger. As every living being strives to survive, we naturally improve to avoid making the same mistakes and adapt to things we were weak in. The upside is that training in this place doesn't drain stamina, and time doesn't exist in this realm, thanks to Orcus. According to him, the reason for putting himself in a spirit blade was to spread the undead, but no one lasted even 100 years of training before asking for death. Anyway, the next stage, stage 3, is the part Orcus made sure to drill into me, but it was the only thing I couldn't try myself, as there are no corpses in this place.

The training that Rukito undergoes in the last stage is very different, as it is not only something that can be achieved through physical training; it requires him to evolve into the next dimension, becoming a fourth-dimensional being. This takes a lot of time, and he needs to reach a state of consciousness that transcends our typical perception in order to break away from his physical body that binds him to the universe. After another thousand years of this, he can finally understand, perceive, and use Metaphysical Void Energy. This is something that was almost impossible to achieve, as Orcus said his own offspring was only able to get as far as stage three. Even though it took a shorter amount of time, it was said to be impossible. But just because he felt it was impossible doesn't mean that there are not many people at this level; it's just that the beings at this level are unknown.

Metaphysical Void Energy was the final step to grasping the concept of the Chaos Void. Its purpose is to help me overcome the one flaw of VE: if I'm in a place without access to it, I'm useless. However, by creating a universe within me, I can fully rely on myself rather than VE. With a universe created inside my body, my will serves as its law, my veins act as connective maps, and my very being becomes a form of Chaos Void surrounding this universe. I now break free from the rules of this universe that prevent infinite energy, unwittingly becoming a paradox myself. With this, not even Orcus can hold me back, as I have transcended what he couldn't at this stage, allowing me to easily defeat him in under a minute.      

After defeating Orcus, he sees the changes in Rukito's personality compared to how he was, as well as how strong he has become. Orcus confronts Rukito, telling him it's impossible to return to the way he was, as he is not the same, and suggests sealing part of his powers. Rukito hates the idea of having his hard-earned powers sealed and transforms his current strength into a form he calls Cosmic Void. With this form, Orcus is able to seal his memories while still allowing his body to remember his time here, reminding him of who he was before the training. Rukito retains the power of VE but cannot use its full extent; however, he can utilize his new sword skills and part of his speed. The seal Orcus planted will slowly unravel in six years. Depending on what Rukito faces, his power will return to him as needed, allowing him to process and overcome the thousands of years of training he underwent, thus reclaiming himself.

Rukito wakes up back where he was, fully pulling out the sword as it feels like he has mastered it.

                 "I knew you could pull it off, Rukito, but now that you’ve been approved by this spirit blade, you seem different—much stronger. You are still the same, right?"

"Yes, Tamako, if it weren't for you, I don't know if I could have done it. But don't worry, I'm still me."

I remember being cut into pieces and healing myself, as well as the sword training and some unknown power that’s related to my teleporting, but my memories are not as clear. One thing I know is that, in time, everything will come back.