Believe it or not, I will start training since I am now three years old. First training is gravity training with a stronger gravity since I've already got used to twice the gravity.
It might not increase my strength fully, but it will prepare my body for heavy lifting and also strengthen my muscles. Since I am a Saiyan, as I discovered not too long ago, I've already expected to use the Room of Spirit and Time for 2 years inside. After that, I can't enter again because I won't be strong enough during that 2 short years, but enough to help me.
The Gravity Training made me exhausted faster, that is without using my breathing technique, as I can't use it for too long or my lungs would burst. Or that's what it feels.
Aside from that, he also told me that my breathing technique is a crude method ad inconvenient because it speeds up my heart to pump faster which causes a strain to the heart, and too much strain will lead to heart failure if my heart can no loger take the hastened pumping.
Then, he taught me of another breathing technique which I'm pretty sure that it shouldn't exist in here, but oh well, I won't say no to learning how to get stronger.
"As you've already noticed, it was from "Kimetsu no Yaiba"." he said while looking at me with a smug face.
"Total Concentration Breathing allows you to be able to strengthen your by absorbing oxygen and distribute it to your body to increase your overall fighting capabilities. If mastered, It will increase by a huge margin which is why a "Hashira" is worth more than 50 Kamado Tanjiro. The starting multiplier of increase is 10 times more because it is the same multiplier once a human turns into a demon."
I nodded to each and all of those words.
"You see, even though your breathing technique have potential of rising its multiplier to 1,000, it will also have bigger strain and shorter time duration of activation that will leave you with either a heart disease or directly kills you. The multiplier of Total Concentration Breathing at maximum is 100, it has a favorable technique without any drawbacks. Even so, I'm surprised you managed to something from "Kenganverse" which is "Advance". Well, time to start training, kiddo."
Then, I started training. Just a few tries later, I already grasp on his to use Total Concentration Breathing in both mind and body.
Then, he taught me the easiest Breath Style, Breath of the Water. It only took me a month to master all forms of it, then I proceeded to learn the next one. The next one, though, it was my choice to learn.
The next Breath Style is Breath of the Thunder. It was fast, and since it was fast, it was also very deadly. One Thunderclap and Flash might enough to severe the head of an Obsidian Soldier. Well, that depends on who used it, and I doubt I could severe the head of an Obsidian Soldier yet.
I mastered the all 6 forms in 4 months. It took longer since the 4th, 5th, and 6th forms are made by a demon who can generate lightning, and the 7th form is technically an form that is slightly behind the Sun Breath style when it comes to firepower, add the speed of Thunder Breath style, you will get a form that could probably kill Akaza. However, Zenitsu doesn't have a Demon Slayer mark nor a Crimson Nichirin Blade, so all he can do is face the newly promoted demon, his senpai under Kuwajima Jigoro, Kaigaku.
Well, the third form is strong and I need to master the first form, the form used as a building block for other forms. The 4th to 6th form is probably the attempt of Kaigaku on learning the first form when he turned into a demon but failed, but they became useful on fighting Zenitsu.
That took 4 months overall.
Next Breath Style was not my choice, I was forced to since the said reason is "You will soon be working with fire now: forging, making and selling charcoals, cooking, and a fire mage!".
It's fine for me to forge, make and sell charcoals, and cooking, but I don't want to be a fire mage. They were always looked up to since they firepower is very high, it's what they say, and was more favorable in destroying an army's plank.
However, I want something flexible, something that have a little bit of everything, a Water Mage. Water Element's advanced stages are Ice, Mist, Vapor, and Scalding Water. These four are the advanced elements under water magic.
Ice magic: It has different range from close quarter to long range fight. The only weakness of this is that it is harder to control due to the water particles being in solid form and it consumes more mana, or what they call as Mind, and heightens the possibilities of exhausting their mana or mind, or known as Mana Exhaustion or Mind Down or Mind Zero.
Mist magic: Aside from most of its spells being supportive type, it can still be deadly since it can fake all the 5 senses of a person inside it if I want to, and kill them while they are trapped in an illusion of reality yet it wasn't. The only drawback is, it consumes more man than Ice magic and only have few attack spells.
Vapor magic: The opposite version of Mist magic, a hot water particles in the air version instead of a cold and condensed water particles. While it can't fake other 5 senses, it can be used for some things like melting a rock. Yes, it can melt a rock and turn it into a lava-state. Its drawbacks is, it can hurt the user itself due to how hot it produces through the water particles in the air.
Scalding Water magic: The opposite of Ice magic that could bun anything, even a lava, which is kinda weird and unbelievable, but it does. It might be too OP, but its range is drastically limited to 10 meters of radius and it is harder to control without learning fire magic.
And so thus I am forced to learn fire magic, although I also learned Lightning magic to learn Firebolt and teach it to Bell to see if he could learn to use Firebolt. If he learned to do so, then he's fated to use Argonaut's magic swords' special abilities.
Well, since it is easier to control the fire through magic than through pumping it with gas or something since that's all I know before, but now I know what they use. However, I'll be using fire magic to better my fire magic manipulation and control while also getting better are forging many things.
Oh yeah, after learning Sun Breathing, I managed to use the 7th form of Thunder Breathing in one month, the form is sure hard to learn. Learning the original style only took 4 months and making different combos with all 12 forms since it doesn't have any set of patterns. Then, I tried to master it but only managed to be able to master it halfway for the next 8 months.
Yeah, it is hard to learn. Tanjiro may not be talented in swordsmanship as he took 2 years to master 1 breath style, it doesn't mean that he's not gifted to do what his ancestors could. Also, he kept breaking his limits during the battle against Muzan, so it's not surprising how he could learn it and master it faster. If he didn't access to his ancestor's memories, I doubt he could kill Muzan.
If Tanjiro learned how to use it early on and during his 2-year training, I doubt Muzan could have a chance against Tanjiro.
It took a year and a half for me to learn Water Breath style, Thunder Breath style, and Sun Breath style. Mastering Water and Thunder Breath styles, but still working on mastering Sun Breah style.
Then, we, me and Kane, decided to call it using its name before it was revealed in the manga, Hinokami Kagura. The thing is, the forms will be called in their english name, which is suggested by Kane.
"Alright, now that you managed to learn these three forms because of their traits — Adaptability (Water), Unpredictability (Sun/Hinokami), and Unforseen Speed (Thunder) — I want you to learn more breath style. To be honest, I want you to learn all Breath Styles and spread it." Kane said with a smile.
"Why?" I asked, obviously.
"Because, I think you are much better at teaching." Kane replied.
"Yeah, I noticed. I noticed that you suck at teaching."
Kane lowered his head in shame and said, "Ugh... My student broke my heart."
"I don't swing that way nor would I do something taboo."
"Ack!!!" he spat out blood, literally.
"Now what? Live a normal life? Fine...."