In this AU everybody lives, Touga, Izayoi, Inukimi, Sesshoumaru, and Inuyasha all live together and the boys are growing up together. English is not my first language so please don't mind some errors. Hope you'll enjoy it! This fic was based on an amazingly funny art by brain-rot-hour on Tumblr
Touga and Sesshoumaru were resting after sword training on the veranda, both sitting with one leg extended with the other knee bended upwards, it was a pacific afternoon, clear sky with a light breeze, the only sounds to be heard were of birds, and the occasional servant in passing, that was letting Touga a little anxious, where was Inuyasha? Things are too quiet, this much silence can only mean one thing in a house with a toddler. As with any self-fulfilling prophecy a few moments later a cannonball Inuyasha throws himself into his father's lap.
"Dad! DAD! Play with me! I've found a new ball" yell the hanyou
Standing up while putting the boy on the ground "Okay pup" he tries to reach for the ball.
"No take!" Inuyasha yells taking the ball away from Touga's reach "Only throw" he says side-eyeing his father mistrustingly.
Suddenly interested in the convo by his brother's antics Sesshoumaru looked up narrowing his eyes, he couldn't believe his brother's shamelessness "That ball is mine! When did you steal it from my room?" he grows and bared his teeth getting up and walking in Inuyasha's direction.
"It is mine now! I find it so it's mine!" Inuyasha grows back to his older brother.
Sesshoumaru takes the ball from his brother's hands with too much speed knocking the little hanyou to the ground, he looked angrily at him while throwing the ball away with force, knowing it would fly far from the family quarters.
"NOO! My baaall" Inuyasha gets up and runs after the toy.
Touga let out an exasperated sigh rolling his eyes inwards "It was wrong of him to take something that is yours but still you shouldn't treat your little brother like this Sesshoumaru"
"It is my ball! This Sesshoumaru does not share his toys. Also he destroys everything he touches" he responds crossing his arms and pouting a little
"Yeah you don't need to share, but you know what you need to do now? Fetch your brother. Go find him and bring him to me" Touga lectured Sesshoumaru "And I want him unharmed you understand me?"
"Yes father" begrudgingly he goes, walking slowly trying to calm himself because he can't hurt his little brother and he wants to do it so badly, who did he think he was to go inside his room and steal his things?
By the smell he can easily find Inuyasha but the sounds coming from the patio from the closest administrative building are strange, how is he hearing thunder with a clear sky? Then the wind changed, and he can smell two youkai close to his brother, Sesshoumaru started to run "Inuyasha wasn't introduced to society yet, they may hurt him and then Father will be mad at me"
When Sesshoumaru can finally see his brother he is between two youkai children, one lean with braided black hair and the other fat and almost bald with an appearance that reminds some kind of lizard, by their youki he can see that despite both being children like him they were somewhat powerful, not even close to this Sesshoumaru but obviously stronger than his 4-year-old hanyou little brother
Both youkai were throwing his ball one to another with Inuyasha in the middle, every time the hanyou jumped to get the ball he was hit by a lightining by the one with braided hair.
"What do you two idiots think you are doing?" Sesshoumaru asked a little appalled by the courage or stupidity of those youkais, he couldn't decide which one it was yet, Inuyasha clearly smelled and looked like royalty despite his hanyou heritage.
"Oh hi!" The braided one turned to Sesshoumaru and measured him with cold eyes "You are Sesshoumaru, right? The Inu no Taisho's heir? Greetings to you! We are the thunder brothers, I'm Hiten and he is Manten"
"I asked you what are you doing?" Sesshoumaru grows back to the youkai.
"Ah, this? We find this abomination trying to steal this ball and decided to get some fun, he must be the spawn of a minor dog youkai or something, do you want to join? It is really fun when he cries!"
"That pup you are hurting is my little brother! He is also a son of the Inu no Taisho, not any minor servant! You! Bald one! Give him to me!"
"I'm not bald! I have a lot of hair too!"
"That is of no importance to me, give me my little brother you vermin, only this Sesshoumaru can make him cry"
"You can't badmouth my little brother!" Hiten yells trying to hit a thunder on Sesshoumaru but fails to hit him.
Sesshoumaru releases his venom whip and lashes Manten's back who releases Inuyasha, with full speed Sesshoumaru takes his brother and puts him beside himself brandishing the ship in Hinten's direction hitting his arm which starts to melt.
"You are going to pay for this your stupid dog!" Hiten runs in Sesshoumaru's direction trying to hit him with a punch.
Sesshoumaru with his claws full of his poison slashes the chest of Hiten giving him a deep cut.
Manten takes his brother and jumps into a flying cloud he conjured they scaped crying for revenge and for their Father's help.
Sesshoumaru was about to give chase, but he sees Inuyasha on the floor in fetal position trembling with fear, he tries to embrace his little brother but notices that his claws are still dripping poison, it is so hard to stop it when he is this angry! But he must not harm Inuyasha, then he decided to calm down until he can stop de venom. He assumed a meditative lotus flower position and did a few breathing exercises his father told him about until he can see no venom in his claws.
Watching his old brother meditating out of nowhere piked Inuyasha's curiosity, he lifted his head and looked around, giving some little whiffs to see if the bad youkai were really gone and moved to sit in the same position Sesshoumaru was, he tried to mimic his brother movements and breathing and that calmed him too, the fear was almost gone now, no trembling or tears just a warm calm.
Sesshoumaru takes Inuyasha by hand and guides him back to the family quarters "Let's go home, you need a bath, you reek like those vermin".
Touga is in the same place and position he was when they left "Did you deal with them?" he asks taking Inuyasha up.
"I could not kill them the way I wanted, they probably are dead by poisoning right now but I wanted some blood, I failed Father" Sesshoumaru answer with his head bowed eyes to the floor.
Touga sighs deeply "Are they the sons of Raijin? The thunder youkai?"
"They called themselves the thunder brothers".
"Hm... you did well pup, you protected your brother, didn't let him alone to pursue them, and applied the calming techniques I taught you" he says messing with Sesshoumaru's hair "I got there at the same time you did, and even knowing I was close you still did right by your little brother, I am proud",
Inuyasha learning that his father was close earlier started crying again "Shh pup, dad is here, everything is going to be all right, they are gone now, your big bro got rid of them, there is no need to be afraid anymore, let's go inside you need to take a bath"
The prospect of needing a bath only made Inuyasha cry harder.