After 2 hours of Inosuke and Tanjiro's training and their friendly spar, they went back and saw Saitama was already awake and reading a book.

Inosuke was annoyed when Saitama was already awake when he says "hey old man! You should tell us that you are now awake, I was excited to fight some damn demons!"

Saitama was not listening to him, but later he looks at the fuming Inosuke, and then Saitama cleaned his own ear while saying "did you say something?" In carefree tone with a calm expression.

"Gnnnnnmmm!" Inosuke's ear produce a steam like he was mad at him, but he can't do anything to this invincible hero because he respect his strength. He just mutter something while looking back.

Tanjiro smiles at Saitama in a warm gentle expression as he says "So mister Saitama, the messenger crow delivered some message today, it says we are moving at night at the mount Natagumo.."

Saitama's eyes lit up, he excitedly grab his pocket blade that he store around his back and says "oh I can't wait to use this weapon again! Old man Sakonji must be proud of me doing some demon slaying hobby! Hm. Maybe I should invent some other breathing techniques!"

Inosuke was extremely curious of Saitama's sword style as he crosses his arm and says "hey old man, do you have breathing technique!?"

Saitama looks at the interested Inosuke as he answers back in calm tone "well it's not like a cool technique, more like a normal type attack for me..."

"Ehh??.....normal attack??...I see.." Tanjiro in awkward tone with an awkward smile. Tanjiro just can't even imagine how strong would be Saitama's normal slash is, but for Tanjiro's perspective, a normal slash from Saitama can even blow up an entire area, more like Saitama's shockwaves can obliterate anything.

Moments later.

The yawning Zenitsu were walking towards them, he was ready for a walk. He already changed outfits.

"I was asleep for a few minutes, so are you guys ready for the journey?" Zenitsu while stretching his arms.

Inosuke while looking at Zenitsu says in mocking tone "hey sleepyhead, are you ready for a walk? Don't try to sleep at night because we are now hunting some asses of the demons!!"

Zenitsu acts cocky while smirking and being proud, he then says "I'm not sleeping during a battle, I am here to protect my dear Nezuko~!"

As Zenitsu pose cool, Saitama and the rest of the squad were watching in uninterested expression. As if they were not impressed of Zenitsu's acting cool pose. They see it as a childish yet unmanly behavior.

"Wow bravo.." bored tone of Inosuke as he claps his hands in sarcastic manner.

Saitama was like...

"Ok..." The poker face Saitama gives a thumbs up like he just force himself to cheer Zenitsu up.

Zenitsu was extremely embarrassed as he didn't expect this, he bath in sweat with a forced smile while staring at them, his cheek flashed red and he was like "eh? Eh??? Ehhhhh!???? Am I a weirdo!?"

"YES YOU ARE!!!" Inosuke laughs hysterically while rolling in the floor.

"Inosuke! Don't mock him!" Tanjiro while pouting and slightly mad of Inosuke's mocking behavior

"Wahhhhhhh!!!! Stop laughing at me Inosuke! Pretend you didn't see that!!!" Zenitsu screams in embarrassment as he run and circle around the tree. Zenitsu tries to calm himself down from overthinking like he is not a weirdo.

Saitama sighed in an annoyance as he goes to change topics.

He stand up as he put the book aside while saying "alright, seems you kids like to see my swordmanship, then I'll do my best..."

"Some cool moves!? You mean you'll show us one of your breathing technique!?" Zenitsu in surprised expression as he stops circling around the tree.

"Hoh! I want to see some of your moves, old man!" Inosuke in excited expression. His nose produce a steam like he was snorting like a bull.

Tanjiro's eyes lit up in excitement as he want to see Saitama's breathing technique again "mister Saitama, please show us one of your best moves, if you can..."

The proud Saitama acts cocky as he slowly walk outside the mansion around the open space where no one would get sweep from his attack.

"This should do it..." The excited Saitama as he look around to check the surroundings while holding his pocket blade.

Tanjiro and his friends were following the hero as they were standing and watching him.

Tanjiro can notice Saitama is using a half sized sword so he offer his sword to the hero as he says "mister Saitama, use my sword, maybe you can do more some cool moves with this" while smiling in assuring tone.

Saitama was grateful of Tanjiro's offer as he smile and says "that would be great, thanks kiddo..." He get Tanjiro's sword and gives a headpat in return.

Suddenly, Saitama's eyes goes wide when he sees the puppy like behavior of Zenitsu and Inosuke offering their swords.

"Huh? What's with your looks!?" Saitama in disturbed expression.

"I want some headpats too!" Inosuke while trying to forcefully offer his sword, he was snorting and likes to have Saitama's headpat.

"M-me too!! I want some good compliments! Not some wierd remarks!!" Zenitsu in begging expression.

Saitama facepalm himself in annoyance of their acts, staring at his squad acting like this, he can't help but to chuckle at them. The hero didn't accept their offer, instead gave them each of his friendly headpat while saying "alright, no need to pressure yourselves..."

Inosuke was snorting with a steam in his nose, he was feeling relieved as he was like "ohhh! This is my first time receiving one! I didn't know this feeling is great"

"I also received some from my grandfather, but asking from mister Saitama feels like I asked my grandfather!" Zenitsu in satisfied tone.

Saitama breaks the headpat as he says "alright, I wasted a minute of my time giving affection, so now I'll try to practice my swordsmanship"

Saitama uses Tanjiro's sword as he pose his attack in an open space.

Saitama's squad were standing and watching the hero with a look of excitement and curiosity.

They were mumbling like,

"Can't wait to see some of mister Saitama's moves..."

"Gnnn! This old man looks like he is about to shatter some of the mountains!"

"Mister Saitama, please don't break my sword...."

Saitama breathes deeply with eyes closed, bending his knees as he focus in his surrounding, he grip the scabbard while his other hand hold the sword to unsheathe it. He was targeting the air with no people around.

The hero was thinking like "I have first and second form, how about third form?? What should I name.....hmmm...."

After a second of his thoughts, he has the idea to do some cool moves.

"SERIOUS SERIES, POWER BREATHING, THIRD FORM....." Saitama goes serious series as the pressure suddenly becomes extremely heavy.

"Ehhh!!???" Tanjiro and his friends were backing off slowly becoming nervous and terrified of Saitama's sudden immense pressure.

Saitama slowly unsheathed his sword, swings it and says "....SERIOUS SLASH!"

[Strong whooshing sound of the blade, generating a deadly wind blade]

[Shockwaves produced that sent the trees flying away around Saitama]

Saitama unsheathed his sword and slash the air so strong it creates a giant wind blade, the wind blade flew and cuts the mountain at the distance into a half, while the area affected produce a strong tremor. Additionally, it produce a shockwave blowing Tanjiro and his friends around, they were pushed back as the trees were sent flying.

After Saitama finished his showcasing technique, he looks back at his friends with a proud smirking look.

But the hero was speechless yet shocked to what he sees on his back...

Tanjiro, Inosuke and Zenitsu was seen hanging around at the big tree as if they were sent flying from a strong shockwaves. Their faces was like giving up and they are slowly becoming unconscious. Their dresses were messed up as they makes whining noises.

"Eh?...did I overdid it..?" Saitama in awkward tone with a nervous yet scared expression.

He looks left and right to see no one is watching him.

Saitama checks them if they are okay and he sighed in relief when he knew they are just unconscious, he smack himself for being reckless again for using too much of his strength. "I was just using a little force of my strength and it ended up a mess....thank goodness the kids are safe...if not, old man Sakonji will haunt me in my dreams..."

Saitama can hear their groan noises as if they are trying to say something..

[Groaning and whimpering sounds]

"M-Mister Saitama....." Tanjiro in tired tone who fainted from Saitama's shockwaves. He wasn't injured but he faint from shock.

The same goes to Inosuke and Zenitsu with a giving up faces

"The.... old man... is a monster...." Inosuke in low tone before he faint.

"I thought.... I'm gonna die...." Zenitsu in forced smile expression before he faint afterwards.

Saitama was flabbergasted as he forced himself to smile but in awkward way, he just climb at the tree to retrieve his squad before going back to the mansion. He was carrying them in his back as Saitama's expression shows regret and pity.

"Damnit, I will suppress myself in doing serious moves.." Saitama while whining and carrying them in his back.

The hero promised himself he will never use some moves that will destroy some large area, a move that can affect the nature but he is not sure if he can promise that since there are some demons that can cause some inevitable death : )

TO BE CONTINUED

"Thank you for reading until the end of my last upload"
-Author